I just found another really swell mapping site. This site is using a Flash interface connected with Google and MSN’s maps. The experience is a lot smoother then that of Google or MSN earth alone. You can slide in out seemlessly and drag the map in all directions with your cursor. I think the satellite imagery is a lot clearer as well.
Check it out. I think it is the best mapping program I have seen.

www.flashearth.com