Here are various internet and Picture Message settings for T-Mobile phones.

MDA and Windows Mobile 5

MMS:

Connection Name: PictureMessaging
Data bearer: Packet data
Access point name: wap.voicestream.com
User name: N/A
Password: N/A
Authentication: Normal
Homepage: http://216.155.174.84/servlets/mms
Advanced Settings (Handsets not equiped with WAP 2.0 may skip this section)
Proxy serv address: 216.155.165.050
Proxy port number: 8080

Connection Name: T-Mobile Internet
Data bearer: Packet data
Access point name: internet2.voicestream.com or internet3.voicestream.com
User name: N/A
Password: N/A
Authentication: Normal
Homepage: None
Advanced Settings (Handsets not equiped with WAP 2.0 may skip this section)
Proxy serv address: None
Proxy port number: None