There are various reasons why you’d do this, and with t-mobile letting you get it without a contract you might want to try to make it work with T-mobileWeb for only $5.99

First here are the basic settings:
Menu->Settings->Wireless Controls->Mobile Networks->Access Point Names->T-Mobile US
I input the following settings:
Name: T-Mobile US
APN: wap.voicestream.com
proxy: 216.155.165.050
port: 8080
Username: Not set
Password: Not set
Server: Not set
MMSC: unchanged from original (http://mms.msg.eng.t-mobile.com/mms/wapenc)
MMS Proxy: 216.155.165.050
MMS Port: 8080
MMC: unchanged (for me it was 310, I believe it is based on your location)
MNC: unchanged (for me it was 260, I believe it is based on your location)
APN type: Not set

Here are the comments from the original commenter about what WORKS, and what doesn’t.
- 3G should work
- Gmail push will not work
- POP3 and IMAP will work (so gmail will work through that way)
- Google maps doesn’t work
- And Android Market DOES NOT seem to work.

For the apps that don’t work you can usually use them when you’re in the wifi network (well not maps, but you get the idea)

G1 News, Misc, News 3g, Access Point, android, apps, google, Maps, Mms, Mnc, Mobile Access, Mobile Networks, Mobileweb, Msg, Names, Port 8080, Proxy, Settings Menu, T Zones, t-mobile, Wap, Wireless Access, Wireless Networks

Yo check it out, we have tried this new service out and it works.

Its called PhoneTag and you can setup your voicemail from any cell phone and even your office number for this service or have all of your numbers under one account.
What happens is when someone leaves you a message this software converts the messages to a text message or email and sends it to your phone so you Don’t have to check your voicemail Ever Again.

The best part is you can Try it Free

PhoneTag automatically converts your voicemail into text and delivers it directly to your mobile phone, Blackberry, Goodlink enabled phone and/or your email account; so you can read your voicemail.

Save time and money by instantly seeing who called you and reading what they said; whether you are sitting in a business meeting or traveling on the road. Your voicemail functionality does not change; it can still be listened to and stored for later use.

PhoneTag works with all Major U.S. carriers and networks including: AT&T, Alltel, Cincinnati Bell, Sprint, Skype, T-Mobile, Verizon, Virgin and more.

Use PhoneTag to unify your mobile, home and work phones into one unlimited voicemail box. With PhoneTag, you can read every voicemail that comes into any of your phone numbers – from anywhere.

News Alltel, Amp, Blackberry, Business Meeting, Cell Phone, Cincinnati Bell, Email Account, Functionality, Goodlink, Mobile Home, Mobile Phone, Phonetag, Skype, Sprint, t-mobile, Text Message, Time And Money, Verizon, Voicemail, Work Phones