The Mac App Store will be available January 6, 2011.
"The Mac App Store is just like the App Store for iPhone, iPod touch, and iPad. So it’s as easy to find and download Mac apps as it is to add your favorite magazine to iPad or a new game to iPod touch. You can browse Mac apps by category, such as games, productivity, music, and more. Or do a quick search for something specific. Read developer descriptions and user reviews. Flip through screenshots. When you find an app you like, click to buy it. " Said Apple.
Find out everything you need to know about developing applications for the Mac, from a complete set of development tools to programming guides to sample code. -
Mac Developer Program - Apple Developer