This application is really cool. It's a way to view earth with real time cloud coverage, lighting, etc. It has tons of options and different ways to view the maps. Globes, full screen, etc. Check it out! This is available for Windows too..
http://www.xericdesign.com/ - $25 single license - $40 for 5 computers - $100 for classroom/small business license.
I'm also writing about the application on my blog @ http://www.cockyjeremy.com
Contact me for requests, etc..
Twitter - cockyjeremy
AIM - cockyjeremy