Here are the AT&T 3G APN network settings for our phone.
Name: Cingular 410
APN: wap.cingular
Proxy: Blank
Port: Blank
Username: WAP@CINGULARGPRS.COM
Password: CINGULAR1
Server: cingulargprs.com
MMSC: http://mms.cingular.com
MMS Proxy: wireless.cingular.com
MMS Port: Blank
MCC: 310
MNC: 410
Authentication type: Blank
APN Type: default,supl,mms
APN protocol: leave as is
Bearer: leave as is
If you need another networks APN settings just let me know and I'll add it!