Brand new user, just getting to know my N770. I know *nothing* about it yet, but so far I'm really enjoying it. Enjoying it so much I'm thinking of picking up an N800 too.

However, I want to say that I can report that bluetooth DUN works on the stock N770 and my stock Cingular 8125 w/ WM5. No PDANet, DLL's, or other hacking required.

You can just use the wizard to set it up the pairing. The warning is because the 8125 does not support file transfers over BT, and has nothing to do with DUN. But you do need to modify the connection settings as above from the Connection Manager. #99* and WAP.CINGULARGPRS, etc. The modem initialization commands are important too, the AT+CG....

Anyway, it does work but not perfectly. Sometimes it takes 3 or 4 tries before the N770 gets the connection, and occasionally I have to soft reset the 8125, but eventually it will connect. Once connected, it's mostly solid and I'm seeing good speeds for normal surfing, email, and streaming audio. I do occasionally get a dropped connection, which is somewhat strange.

My $.02:
You don't really *need* to have a tethering packaged added to your account. The official stance is that you must have it to tether or you will be charged for every kb. I've followed the discussion for years over on HowardForums; this is a hotly debated topic. Head over there and do a search for 'cingular' and 'tethering'. Lots of reading will follow. FYI, I do not have a 'tethering' plan and have never had an extra charge for the rare tethering to my laptop to check email or the news when I'm away from an internet connection. We're talking maybe 20-30mb of data over the course of a weekend, maybe once a month. No, I wouldn't use it to stream bittorrents, but in my experience it's fine for 'light' surfing and email. Again, just my opinion, so take it with a grain of salt, as they say.