Works for me!
It works outstandingly for me:
Phone: Verizon XV6900 (aka HTC Touch - CDMA EVDO rev A, no wifi), WinMo 6.1 running Internet Sharing utility.
Archos 80, "Staples Special" (1 Ghz/512 MB RAM/7 GB storage - listed as 4GB, go figure), ICS, FW 4.0.6
How I did it:
1. BT pair the phone and tablet (duh ;)
2. Make sure they are connected - tap the phone device name in the Android BT settings list so it shows connected
3. Start ICS ("Internet Connection Sharing" - they had that acronym long before any Google Android existed ;) on the WinMo phone, tap its "Connect" soft key.
4. Android settings: "More.../Tethering & portable hotspot/Bluetooth tethering" check marked (yeah, I thought that meant the Archos would share its connection - dunno about that, but it is working in the opposite direction for me - go figure).
I streamed a TunedIn radio stream for several hours this way at a hotel recently (good thing I have the "unlimited" data plan grandfathered, but looks like I only used about 20MB, picking 40Kbps stream).