Follow these instructions, Please Note that this process and these settings are for T-Mobile and Windows XP Users. Also Note that these are meant as a reference and are not a guarantee seeing as T-mobile has changed these settings before. These are confirmed as of August 3, 2007:
Install latest version of Desktop Manager
go to the control panel on your computer
go to Administrative tools
go to computer management
on the left side click Device manager
on the right side click on Ports (Com & LPT)
Write down the number on the ports that say Rim Virtual serial Port V2
go back to the control Panel
go to network connections
go to file
go to new connection
go to connect to the internet
click set upconnection manually
click connect using dial up modem
checkmark the box that says Standard modem and has one of the Port Numbers you wrote down earlier
Uncheck all others
For the ISP Name you can put whatever you like I choose Blackberry
For the Phone Number enter the following exactly: *99***1#
Leave Username, Password and Confirm Blank
Uncheck Make this the default internet connection, unless you really want to make this your default internet connection.
Checkmark Add a shortcut to this connection on my desktop
At this point a window should pop up, close this for now.
Go back to the Control Panel
Click Phone and Modem Options
On the top of the window that pops up click the tab that says Modems
Click on the modem you used earlier it should be Standard Modem and have the same port number from earlier.
Once you have it highlighted go to the bottom and click Properties
at the top of the window that opens click on the tab that says Advanced
In the Extra initialization Commands box, type in the exactly: at+cgdcont=1,"IP","wap.voicestream.com"
Go back to thecontrol Panel
Next go tothe Network Connections Folder
Next Right Click On the New Connection we just made and select Properties
On the top on the window that pops up click the tab that says Networking
Click the settings button
Another window should pop up, Make sure that Enable LCP Extensions is Check marked and make sure that Enable software compression and Negotiate Multi-Link for Single Link Connection are both Un-Checked.
You can close all the windows if you haven’t been closing them already.
Open Desktop Manager and connect the Blackberry
Look for the Connection shortcut on the Desktop and double click it.
At the bottom of the Desktop Manager it should say Connected if it is not go to Options then go to Connection Settings and click connect, it should tell you that it has found it, if it doesn’t you have a separate problem.
Once connected to the Desktop Manager click on the shortcut to the connection that we made earlier, it should be on the desktop.
Check the box that says Save this Username and password for the following users:
Click on Anyone that uses this computer
Click Dial. It should dial and connect.
Reasons for failure to establish the connection to the internet:
The desktop manager is closed. The desktop manager MUST be open the whole time you are using the internet!
On the Phone APN settings you have ANYTHING there, the APN settings MUST be Blank to establish connection.
You don't have to have desktop manager open. As long as blackberry device manager is on, as mention above on my post.