Mac OS X 10.6.6

Mac OS X 10.6.6 was an update to Mac OS X 10.6 released on January 6, 2011. It had the following features:

The Mac App Store, a new application you'll find in the Dock, includes the following features: Additional improvements
 * Discover Mac apps: Browse featured apps, top charts, and categories, or search for something specific.
 * Buy and install: Easily purchase apps with your iTunes account. Apps install in one step and are quickly available from the Dock.
 * App updates: The Mac App Store keeps track of all your purchased apps and notifies you when free updates are available.
 * Security updates.
 * Addresses a cropping issue with some postscript printing in landscape page orientation.
 * Resolves an issue with some Macs (that have in ATI graphics card) in which the mouse pointer movement could become erratic if an external DVI display is connected.

External References
Apple: About the OS X 10.6.6 Update