I Recently was playing with my Android.
After installing a new ROM I noticed my data network was not working.
After some searching around I found the following:
Password: CINGULAR1 (must be in CAPS)
Proxy: leave blank
Port: leave blank
Password:CINGULAR1 (yes this is in CAPS)
Server: leave blank
MMS Proxy: wireless.cingular.com
MMS Port: 80
APN Type: leave blank