What you have is pretty much what I've got:
The T-Mobile "MDA", which is some model by HTC. I have been using same as my modem for my computer at work (where that's the only way for me to go online)
Lessee if I can explain how I did it;
>bought a bluettoth usb dongle by Belkin (my carpc usb dongle is by Iogear...)
>installed software for dongle; it leads you through config
>when it gives number to dial up, enter *99#
>when you click on the icon to connect, your phone will tell you that a bluetooth device is trying to connect. you allow it to, and will have to make up a security code, 4-digit no.
>once the phone and the pc dongle have "paired", which means they're communicating, then you should be able to click on internet explorer and go online, a wee bit faster than a good dial-up speed.
I must admit that the above are some pretty lame instructions. That's generally how it's done, but due to a HD crash, I couldn't look on my carpc to see details (as I haven't re-installed my bluetooth driver). Also, T-Mobile cust svce can hook you up with clear instructions. Look on their website. I found it way back when; it just takes a bit of looking. Check this out:
Probably one of the smarter guys will chime in and give clearer directions, but if you use your head and follow my gen'l instructions, you should be online in no time.
Remember that you have to buy a bluetooth dongle to insert in your pc's usb, unless you have a laptop already bluetooth enabled. There is no actual cable connection between the phone and the pc.
Last but not least, because I am running a desktop pc as my carpc, I installed a Netgear wireless PCI card, which permits me to use my Verizon high-speed internet connection when I'm near the house. Also, i do use other networks wherever I go, as long as they give permission. It's nice to have high-speed AND dial-up, so somehow, someway, i can always get connected. Got the Newtgear at Best Buy $75.