While at the Apple store I purchased one of these mice. Its' silver and matches my 12" Powerbook. The base is black. It has a button on the side that when you press it a compartment opens up and inside that compartment is a USB adaptor plug. It has a scroll and is a two button mouse.
Its a small adaptor, and you plug it into your USB port on your powerbook or desktop keyboard, and your wireless. The mouse has a great feel and is solid without rattles. The clicker is quiet. Kensington has supported OSX with great software for their mice in which you can customize your mouse buttons.
If you need a mouse for on the go, you can pull the USB plug, pop open the mouse, stick the adaptor in and your portable without wires and tangles.
Whats good about it at home or work, is you don't have to plug any power supplied wireless adaptor that most wireless mice have into your already crowded surge protector. Clean and uncluttered. The mouse is only $39.95.
Kudos to Kensington for supporting Apple with great products.
Kennisgton Pocket Mouse Pro Wireless