I decided dial-up with my Razr on T-Mobile wasn't enough.
I have T-Zones (recently renamed, apparently) and wanted to figure out what I could do.
3+ hours of Google & monkeying around, I got it.
I found this site:
http://www.gruups.com/tzones/
and used it as my baseline.
Here's what I did to make it work:
Type:Packet Data
Phone Number to dial: *99***1#
APN: wap.voicestream.com
username:10-digit t-mobile phone number*
password:<blank>
ADVANCED-
Proxy: 216.155.165.50 port:8080

*It was this that allowed web browing and e-mail, without it, I only got e-mail.