There are many reasons why Austin got the GP.
Austin is/has:
1) known holding large events each year (SXSW and ACL)
2) relatively in the center of the state and the country
3) Incredibly close to the border (compared to NYC or Indy), so they can milk the Latin American money
4) a great airport (compared to SAs) with a lot of area to park aircraft for all the VIPs
Last week they announced their website along with the location of the track (
http://formula1unitedstates.com/index.html). Notice how close it is to the airport, much like the track in Malaysia. Not only that but its right off the new tollway.
Personally I can't wait until 2012, and now that they've gone to see Red McCombs the deal is going to get done