Cingular, following the discontinuation of the V600, has decided to launch a full product recall of the device. Cingular will send you a V400 and a box to send your V600 in. When they have repaired your V600, they will send it back to you with a box to send the V400 back.
Apparently, the problems were more widespread than the original firmware problems seen. Cingular V600s will also have part of their antenna array replaced. To start the recall process for your V600, call 1 (800) 201-6235
Cingular wants to make it clear that many, but not all V600s are under recall (they will check your phone when you call), and that AT&T Wireless V600s are not affected currently.