While there's good BBQ in Austin, if you have an afternoon, you should go out to Black's and/or Smitty's in Lockhart, just about 30 minutes out of town
There's plenty of pay wifi in the airport, but so far Amy's Ice-cream (around gate 11 or 12 in the little good court) has kept it's free wifi up. The SID is something like "Amys Airport" So skip the T-Mobile and other pay stuff and get free internet!
