The next problem I ran into is sending text messages. I believe this is due to my old AT&T Wireless (blue) SIM card. I found instructions on how to set the SMS Center phone number.
*Download Any Cut from the Market.
*Open Any Cut and click "New shortcut"
*Click "Activity", then "Testing", then "OK"
*Go to your home screen and click "Testing"
*Click Phone information
*Scroll all the way down
*Where it says "SMSC:" ...
I found the AT&T SMSC number in the howardforums archives: +19078319301