My friend Joel asks...

"I'm also looking for a bluetooth mouse to replace the bluetooth mighty mouse that came with my iMac..." 

Is there a good Microsoft Bluetooth mouse that will work with the Mac?

Wireless Laser Mouse 8000

As for a Bluetooth mouse there's the Wireless Laser Mouse 8000 which I use at the office (it's a handful but very comfortable)...  

And I believe that it works with the Mac. (The upcoming 8000 desktop does... more info here)

As an FYI, here's how to set up a MS Bluetooth mouse with a Mac, from Apple's site: