Police services provided by the Houston Police Department.  
Fire/Rescue/EMS services provided by the Houston Fire Department.

For airport operations, see Texas Wide Area Radio Network (TxWARN) Motorola Trunked Radio System.

Atlantic Southeast Airlines ("Candler") doing business as Delta Connection.
Chautauqua Airlines doing business as Continental Express, Delta Connection and United Express.
Colgan Air doing business as Continental Connection.
Comair doing business as Delta Connection.
ExpressJet Airlines ("Jet Link") doing business as Continental Express.
PSA Airlines doing business as US Airways Express.
World Airways doing business as Sonair.

Continental Airlines Ramp Control controls ramps for terminals A, B, C, D and E. 

Air Traffic Control:
Arriving Aircraft: TRACON > Tower > Ground > Ramp Control
Departing Aircraft: Ramp Control > Clearance Delivery > Ground > Tower > TRACON
Houston Terminal Radar Approach Control (TRACON)
126.225  S [ CSQ ] Automatic Terminal Information Service (ATIS) - Construction
124.05   S [ CSQ ] Automatic Terminal Information Service (ATIS) - Main
128.1    S [ CSQ ] Clearance Delivery
122.4    S [ CSQ ] Flight Service Station (FSS)
119.95   S [ CSQ ] Ground
121.7    S [ CSQ ] Ground - East
118.575  S [ CSQ ] Ground - West
120.725  S [ CSQ ] Tower - Runway 8L/26R
125.35   S [ CSQ ] Tower - Runway 8R/26L
135.15   S [ CSQ ] Tower - Runway 9/27
127.3    S [ CSQ ] Tower - Runways 15L/33R and 15R/33L

Aviation - Airlines:
Air France is serviced by Atlantic Aviation.
Aviacsa, Emirates, Funjet Vacations and Sonair are serviced by Menzies Aviation.
129.75   S [ CSQ ] Aeroméxico
128.875  S [ CSQ ] Air Canada / Air Canada Jazz
129.325  S [ CSQ ] American / American Eagle ("Eagle Flight")
130.475  S [ CSQ ] British Airways ("Speedbird")
129.925  S [ CSQ ] Continental - Deicing
130.9    S [ CSQ ] Continental - Load Planning
130.725  S [ CSQ ] Continental - Maintenance
129.3    S [ CSQ ] Continental - Operations
130.825  S [ CSQ ] Continental - Ramp Control - North (Terminals C and D)
131.275  S [ CSQ ] Continental - Ramp Control - South (Terminals C and E)
121.625  S [ CSQ ] Continental - Ramp Control - West (Terminals A and B)
128.925  S [ CSQ ] Continental Connection (Colgan Air) - Operations
136.675  S [ CSQ ] Continental Express (Chautauqua) - Operations
129.675  S [ CSQ ] Continental Express (ExpressJet) - Dispatch/Maintenance
131.825  S [ CSQ ] Continental Express (ExpressJet) - Maintenance
136.65   S [ CSQ ] Continental Express (ExpressJet) - Load Planning
136.55   S [ CSQ ] Continental Express (ExpressJet) - Operations
131.85   S [ CSQ ] Delta / Delta Connection - Dispatch/Maintenance
129.5    S [ CSQ ] Delta / Delta Connection - Operations (includes Miami Air International)
131.625  S [ CSQ ] DHL
131.15   S [ CSQ ] Emirates
131.925  S [ CSQ ] FedEx
131.25   S [ CSQ ] Northwest - Dispatch
130.1    S [ CSQ ] Northwest / KLM - Operations
130.55   S [ CSQ ] Taca
130.05   S [ CSQ ] Tradewinds
130.3    S [ CSQ ] United / United Express (includes Allegiant Air)
129.425  S [ CSQ ] UPS
130.175  S [ CSQ ] US Airways ("Cactus") - Operations/Dispatch/Maintenance
130.625  S [ CSQ ] VivaAerobus

Aviation - ARINC En Route Service:
131.65   S [ CSQ ] South Central USA (available above 20,000 feet and on the ground at IAH)

Aviation - Corporate:
130.8    S [ CSQ ] ConocoPhillips
131.725  S [ CSQ ] El Paso Energy (license frequency changed in 2008 to 130.2)
129.825  S [ CSQ ] Exxon Mobil

Aviation - Fixed Base Operators:
129.025  S [ CSQ ] Atlantic Aviation
131.6    S [ CSQ ] Landmark Aviation
130.6    S [ CSQ ] Menzies Aviation

Airline Ground Operations:
Most Continental Airlines operations are on a 900 MHz OpenSky trunked radio system.
460.775  R [127.3] Air France
460.675  R [114.8] American
464.475  R [ 82.5] British Airways "if need me holler on channel 1"
461.7875 R [127.3] Continental - Aircraft Interior Cleaning (Servisair?)
452.4625 R [d 125] Continental - Aircraft Lavatory and Water Service (AccuFleet)
460.75   R [127.3] Continental - Aircraft Maintenance - avionics? B73, battery 2 temp indicator
460.85   R [127.3] Continental - Aircraft Maintenance - E18, E17, cabin stuff?, Hangar B, super tug
460.7    R [127.3] Continental - Catering (Chelsea, Ch. 1) - C30, C, E10, E22, 29, 26, north side ramp
461.325  R [127.3] Continental - Catering (Chelsea, Ch. 2) - 84D, 81A, 83A, B83, north side, 71, 69, 71, 69, 74, south side guys
463.425  R [127.3] Continental - Catering (Chelsea)
461.8875 R [MTRBO] Continental - Electric Carts/Wheelchairs (PrimeFlight Aviation Services)
460.9625 R [127.3] Continental - Ground Equipment Maintenance
461.225  R [d 072] Continental Express - Lavatory and Water Service (dispatch, aircraft, soak, final service, lav only, B72, water)
464.05   R [127.3] Continental Express - Ramp Security
460.825  R [103.5] Delta
461.5625 R [d 311] Emirates
463.75   R [127.3] ExpressJet - Aircraft Maintenance
463.7375 R [d 071] ExpressJet - Aircraft Maintenance (was simulcast with 464.6375)
461.8125 M [d 411] ExpressJet - Unknown - pod 7, B65, B60-B66, pod 8, aircraft, in the food court, 62A, B83A
461.1125 M [114.8] FedEx - Ramp
466.1125 M [114.8] FedEx - Sort
464.775  R [d 343] KLM
460.825  R [156.7] Lufthansa?
457.7125 M [d 612] UPS
461.1625 R [141.3] US Airways

Federal Government:
165.6875 R [100.0] Customs Inspectors
162.325  S [     ] Federal Aviation Administration - Data Bursts (Low Level Windshear Alert System?)
168.9625 M [ P25 ] Transportation Security Administration (TSA) - Body Scanner Operators
169.3    M [ P25?] Transportation Security Administration (TSA)
172.15   R?[ P25 ] Transportation Security Administration (TSA)
172.9    R [n 001] Transportation Security Administration (TSA)
410.075  S [     ] Federal Aviation Administration - Data (Automated Surface Observing System?)
932.7    S [     ] Federal Aviation Administration - Data

Miscellaneous Airport Services:
464.7    M [203.5] Airport Concessions
464.375  R [d 516] Allied Aviation Fueling
463.3875 R [d 125] Atlantic Aviation
464.575  R [123.0] Consolidated Rental Car Facility - Shuttle
467.8125 M [ 85.4] Menzies Aviation
489.15   S [     ] TerminaLink Train Data
489.25   S [     ] TerminaLink? (morse)
492.15   S [     ] TerminaLink Train Data
492.25   S [ 67.0] TerminaLink? (open mic/keyed-up with dead air)
464.625  R [ 82.5] Wackenhut Security
152.3    S [ CSQ ] Yellow Cab - Staging (Base)

Parking Shuttles:
463.9    S [103.5] Air Park IAH
464.025  R [d 125] Allright Airport Parking
462.225  R [123.0] Ampco Express Airport Parking
464.125  R [118.8] EcoPark
452.15   R [d 114] Park N Fly
463.575  R [233.6] Parking Spot
464.6    R [136.5] Parking Spot 2? - paul, pickup at oscar, unit 30, india, paul, one on north side, row Q
451.7875 R [d 125] Pre-Flight Airport Parking
452.2    R [118.8] Service Park

Airport Hotel:
452.875  R [d 244] Houston Airport Marriott - Event Services (has phone patch)
461.0125 R [203.5] Houston Airport Marriott - Operations/Maintenance

Unidentified:
460.8    R [     ] ETA into gate 21
461.05   R?[     ] Continental Express Maintenance? - 5/5 morse heard only
461.0625 R?[MTRBO] Continental? - 5/5 TRBO
463.4    R [127.3] Continental?/Chelsea? - 5/5 Spanish/English, you need to physically be here
464.3    R [100.0] ?
464.55   M [d 412] Continental Cargo Handlers or Ramp Security? - aircraft 703 at D11 needs to be secured, jetway, tell them to go to terminal E, aircraft 18 cleaners haven't been on it yet, plane is on D5 (continental 777), aircraft 14 at gate C16 status, C16 secured call ops with times
469.5375 I?[d    ] brief voice

Obsolete (no longer used):
129.4    S [ CSQ ] Southwest
130.0    S [ CSQ ] US Airways / US Airways Express (license canceled; obsolete?)
130.65   S [ CSQ ] Frontier (license moved to HOU)
131.475  S [ CSQ ] Pakistan International
131.875  S [ CSQ ] Shell (assumed obsolete, IAH base is now closed and license canceled)
151.865  S [d 423] Atlantic Aviation (assumed obsolete)
453.0125 R [d 654] Xpress Park (assumed obsolete, is now Parking Spot 2)
460.725  R [d 627] Continental - Wheelchairs (Associated Building Services, Ch. 1) (assumed obsolete)
461.75   R [127.3] Continental - Aircraft Lavatory Maintenance
462.3375 R [131.8] Frontier (moving to HOU?)
463.3    R [d 343] Northwest (assumed obsolete, Delta channel in use)
464.325  R [203.5] United (assumed obsolete)
464.4375 R [d 244] Southwest
464.6    R [d 743] America West - Customer Service (assumed obsolete; US Airways repeater still in use)
464.6375 R [d 306] ExpressJet - Aircraft Maintenance (was simulcast with 463.7375)
464.675  R [d 114] Continental - Electric Carts (Associated Building Services, Ch. 2) (assumed obsolete)

Related Links:
AirNav
FAA Airport Diagram

Notes:
Pod 5 is Continental Express Gate B84 area