Then I went to synch it with my Mac using the swoopy new wireless Bluetooth. It turns out that while iSync supports the Nokia 6131, it doesn't support the Nokia 6131 NFC. So I wrote my own iSync connector. This enables me to transfer pictures and movies from my phone, load pictures to my phone (screen backgrounds like Kim Possible and such), ringtones (like the Kimmicator tone), all that stuff without paying anybody a dime!
That solved, I went to use it as a modem for internet connectivity when I'm somewhere that doesn't have free wireless (Logan airport comes to mind). The phone informed me that I needed to subscribe to GPRS packet service. So I called up T-Mobile and turned it on. But when I tried it, I still got the "subscribe to packet" message.
I called T-Mobile tech support, and they told me I needed to install the Nokia suite. This is just some windoze-only config software, and I explained that something else must be required. So they told me to go to the control panel. I again pointed out that I'm not running something that obsolete. Eventually I worked out on my own that I really only needed to do one thing: on the phone, go to
Settings → Configuration → Personal config. settings → My Access Point → Access point settings → Bearer settings → Packet data access point
and set it to
"internet2.voicestream.com". That's it. One (deeply buried) setting, and suddenly it works! With Bluetooth, I don't even need a cable like my old phone! It also supports IR, should I need that sometime.