What are unlocked cellphones and why would you want to Unlock it?
The short of it is, Carriers like AT&T and T-Mobil “Lock” their phones to their network, to prevent you from switching between them.
By unlocking your phone, you can freely use a sim card from AT&T, T-Mobile or any other carrier that uses SIMM cards. (Carriers [...]

I can never remember the Username and password for the TCP settings for my blackberry.
Here they are, the important settings in bold.
Internet Settings:
Name: MEdia Net
Homepage: http://device.home
Service Type 1: WAP
Gateway IP: 66.209.11.61
Port 1: 9201
Domain 1: Blank
Service Type 2: WAP
Gateway IP 2: 000.000.000.000
Port 2: 9201
Domain 2: blank
DNS 1: 000.000.000.000
DNS 2: 000.000.000.000
Timeout: 15 minutes.
CSD No 1: 14152441012 or 18472549271
Username: WAP@CINGULAR.COM (required [...]