jailbreaking prayers have been answered. Hacker iH8Sn0w updated the Sn0wbreeze tool, adding support for Big Red handsets running iOS 4.2.7 and finally allowing those who have forsaken AT&T to bring the magic of Cydia to their phones without the cumbersome need for tethering. The usual caveats apply: you'll have to get your hands on a copy of iOS 4.2.7 (just do a little Googling) and there is always a very small chance that something could go horribly wrong and you'll wind up with a very shiny paperweight. Mac users will have to sit this one out -- Sn0wbreeze is a Windows-only affair. Hit up the source link to get your iHack on.
[Thanks to everyone who sent this in]