Today, Apple announced that the Mac App Store will open for business on Jan'6, 2011. Mac App Store will be available in 90 countries at launch and will feature paid and free apps in categories like Education, Games, Graphics -- Design, Lifestyle, Productivity and Utilities.
"Mac App Store lets you browse new and noteworthy apps, find out what's hot, view staff favorites, search categories and read customer ratings and reviews. Like on iPhone, iPod touch and iPad, you can purchase, download and install apps in just one click and start using them immediately. Purchased apps can run on all of your personal Macs and updates are delivered directly through Mac App Store so it's easy to keep all of your apps up to date."
Mac App Store is available to Mac OS X Snow Leopard users as a free download through Software Update.
Mac developers set the price for their apps, keep 70% of the sales revenue, aren't charged for free apps and don't have to pay hosting, marketing or credit card fees.
More Info: developing for the Mac App Store