HTC Hero on AT&T 3G
Hope this helps. Let me know!
Here are your AT&T APN settings/instructions
from the home screen, hit the menu key.
tap on settings.
tap on wireless controls.
tap on mobile network settings.
tap on access point names
hit the menu key.
tap on new APN.
user: WAP@CINGULARGPRS.COM (all caps)
pass: CINGULAR1 (all caps)
mms proxy: 188.8.131.52
mms port: 8080
Connection name: AT&T Media Net
Data Bearer: Packet data
User name: WAP.CINGULARGPRS.COM
Prompt password: No
Password: empty; alternately "CINGULAR1" -- try both empty and with the password if you aren't having luck.
Leave proxy stuff empty. That stuff is only for MMS, etc., not generic data.
These settings give me EDGE data on AT&T with my unlocked phone.
Phathom - Tmobile 3G is at 1700mhz band which is unique in the world. Phones have to be specifically designed for TMobile see here