I purchased a Rocketfish Bluetooth USB Keyboard & Mouse (model RF-BTCMBO) and found that the mouse works but its wheel is evidently not supported in GNU/Linux.
I run Mandriva, but I've seen on the Ubuntu forums that users have not been able to get it to run for them either until someone found that swapping the Rocketfish dongle with a generic one cured the problem. Unfortunately its not as easy as that.
I've written a simple workaround that makes the process much easier, although not automated. (this is due to the need for the Bluetooth devices to do a scan for the mouse in search mode in real time).
Here's the script, tailored and commented for typical Ubuntu users but can be easily adapted to GNU/Linux distributions that allow root:
http://www.user.dccnet.com/jonleblanc/code/bmw.txt
NOTE:
I tried putting the 2 USB Bluetooth dongles side-by-side and booted up the machine. When I ran the script the hidconfig command segfaulted and locked out both the keyboard and mouse! I separated the 2 dongles by about 6 inches and hit the reset button. All has been running properly again after that.