Wirelessly posted (HTC Diamond: Mozilla/4.0 (compatible; MSIE 6.0; Windows CE; IEMobile 7.11) Sprint MP6950SP)
Sounds like a tower near you has gone down. I think Sprint and Verizon do have agreements to use some of the same towers when roaming. Not all though. You could try loading a different PRL that would point your device to a different tower. Look here:
http://www.corolada.com/prl/
It might not be worth the trouble if you aren't going to be there long.