The release notes for the latest build of 10.6.8 will introduce changes to the Mac App Store that will ready the system for the arrival of Lion. It is expected that Apple will officially announce the launch date for Lion at the upcoming WWDC event in June.
The update will “enhance the Mac App Store to get your Mac ready to upgrade to Mac OS X Lion”.
The update also tackles the Mac Defender malware and will remove it from your system if it is installed.