Great news for MAC users : With the release of Google Earth 4.1 (beta) a lot of Mac users can use the SpaceNavigator with Google Earth on the Mac ! You are not familiar with SpaceNavigator ? It's a 3D Mouse device which lets you control Google Earth...like you never did before: Here is the video demonstration of gearthblog. And for technical details, click here.
ps. I would like to dedicate this post to a MAC lover, who bought the SpaceNavigator in december without knowing that it wasn't working on GE and who is soo happy now :-)