there are people on here that have alltel but most don't admit it. you should be fine with most roms unless they specify a carrier in the description.
vista will take some tinkering to use. there are drivers you have to download. if you look in the apache thread it should be labeled vista drivers a few pages forward (2 or 3 I think.) if u don't find it.. do a google search for "usba.zip".
and most new roms have fixed the vista tethering problem
hope that helps