I went to best buy to buy a new magic mouse for my 24 inch imac. It wasn't out on display but it was in the back and but an employee got it for me. I was surprised when in the instructions it said this: " To use your Apple Magic Mouse and its full range of features, update your Mac to Mac OS X version 10.5.8 or later and install the Wireless Mouse Software Update 1.0; or update to Mac OS X version 10.6.2 or later. " On the apple site it says this: Mac OS X v10.5.8 or later with Wireless Mouse Software Update 1.0* or Mac OS X v10.6.1 or later with Wireless Mouse Software Update 1.0. It must come out within a few days or hours.