Instead of just hanging around at airports while waiting for your flight, Google said it will be offering free Wi-Fi to travelers across the United States starting Tuesday at 47 airports.

The free WiFi service began on Nov. 10 and runs until Jan. 15, 2010.

The free service - which will be used to promote Google's products - follows Google's partnership announcement with Virgin America to offer free in-flight Wi-Fi during the same period.

What's the catch? When users logon to Google's free WiFi at an airport terminal, they will be asked to try out Google products, set their homepage to and donate to charities.

Google says customers have the right to decline any of these offers.

Meanwhile, Yahoo has also jumped onto the scene by offering free WiFi at New York's Times Square for a year.

The free WiFi service will be available during peak travelling time which includes Thanksgiving, Christmas and New Year’s holidays.

The Federal Aviation Administration expects over 100 million people to travel these airports between during the time that Google is offering the free WiFi.

The free WiFi will be available at the following 47 airports:

Austin (AUS)
Baltimore (BWI)
Billings (BIL)
Boston (BOS)
Bozeman (BZN)
Buffalo (BUF)
Burbank (BUR)
Central Wisconsin (CWA)
Charlotte (CLT)
Des Moines (DSM)
El Paso (ELP)
Fort Lauderdale (FLL)
Fort Myers/SW (RSW)
Greensboro (GSO)
Houston (HOU)
Houston Bush (IAH)
Indianapolis (IND)
Jacksonville (JIA)
Kalamazoo (AZO)
Las Vegas (LAS)
Louisville (SDF)
Madison (MSN)
Memphis (MEM)
Miami (MIA)
Milwaukee (MKE)
Monterey (MRY)
Nashville (BNA)
Newport News (PHF)
Norfolk (ORF)
Oklahoma City (OKC)
Omaha (OMA)
Orlando (MCO)
Panama City (PFN)
Pittsburgh (PIT)
Portland (PWM)
Sacramento (SMF)
San Antonio (SAT)
San Diego (SAN)
San Jose (SJC)
Seattle (SEA)
South Bend (SBN)
Spokane (GEG)
St. Louis (STL)
State College (SCE)
Toledo (TOL)
Traverse City (TVC)
West Palm Beach (PBI)

Follow the link for more information on Google's free wifi: