Apple's Snow Leopard will be available this Friday (8/28)

This Friday, Apple’s new operating system Snow Leopard 10.6 will be available for sale at MacMedics. You can purchase an upgrade from Leopard (10.5) for $29.95

This new OS has been in development for a long time, and will offer a number of improvements. For starters 10.6 is dropping support for Power PC Macs, so the overall size of the OS will be smaller. This will save about 7 GB’s on your hard drive, and the amount of RAM the OS takes up will be considerably smaller.
http://www.apple.com/macosx/refinements/
Some of the improvements in 10.6 are a faster finder and quicker Time Machine back up process, plus a new look for Exposé and Stacks. Snow Leopard will also offer a faster “wake up” and “shut down”.
http://www.apple.com/macosx/exchange/
Snow Leopard offers full support for Microsoft’s Exchange. All of Apple’s applications like iCal, Mail, and Address Book will allow you to sync and share data with an Exchange server.