First I pointed you to an unofficial update tool to get the Windows Phone 7 updates on your AT&T handsets early.
Then, this update was posted on update tool developer Chris Walsh's site:
tl;dr: Do not use my tool to update your phone. [...] Most problematic, Microsoft tells me that updating in this manner will place devices in a "non-serviceable state". In its blog post describing the situation, Microsoft instead says devices updated in this manner "may" no longer receive updates.
-- Chris Walsh
Horror. Sadness. Until just now: