Supported Devices:

MacBook Pro:
MacBook Pro (Aluminium) Early 2006 or later
MacBook Pro (Unibody) Late 2008 or later 

MacBook:
MacBook (Polycarbonate) Mid 2006 or later
MacBook (Aluminium Unibody) Late 2008
MacBook (Polycarbonate Unibody) Late 2009 or later

MacBook Air:
MacBook Air (Aluminium Unibody) Early 2008 or later
MacBook Air (Tapered Unibody) Late 2010 or later

iMac:
iMac (Intel) Early 2006 or later
iMac (Aluminium) Mid 2007 or later

Mac Mini:
Mac Mini (Intel) Early 2006 or later
Mac Mini (Intel Unibody) Mid 2010 or later

Mac Pro:
Mac Pro (Cheese Grater) Mid 2006 or later

Initial Release: 10.6.0 (August 28 2009)
Latest Release: 10.6.8 (July 25 2011)

New Features:
- Intel Only
- Last OS to support PowerPC Applications
- App Store
- Full Multi-touch support
- Improved Quicktime
- System enhancements