AT&T tethering cross-country

I tried AT&T tethering during my bus trip to PyCon 2011. My bus stayed on the highways, for the most part. The results:

• It was trivial to set up
• When it worked, it worked well
• Through most of Washington State, all of Idaho, 95% of Montana — in fact, through most of all the way from Seattle to Milwaukee — I didn’t have a 3G signal at all. I had Edge, GPRS, or no signal
• Tethering on 3G was fine. Tethering on Edge was slower, of course, but fine. I didn’t try tethering on GPRS

YMMV.