On January 6th, OS X 10.6.6 was released with the Mac App Store, as promised back in October. This is Apple’s equivalent to the App Store for iPhone, iPad, and iPod Touch — but exclusively for the Mac. With it, you are able to purchase (using your iTunes account) applications for the Mac, browse software, and install updates to software previously purchased in the App Store.

The Mac App Store looks much like its iTunes counterpart. Once OS X 10.6.6 is installed, a new icon will appear on the Dock and the traditional Mac OS X Software… entry in the Apple menu will be replaced with App Store.

Launching the App Store will let you immediately browse for new and updated software, with buttons along the top to allow quick navigation to featured items, different categories of software, a listing of your past purchases, and any available updates to software you had previously downloaded.

The App Store is not without its quirks, however. When launched, it indicates the status of apps as well as their price, similar to the iTunes store. So if you have iWork or iLife installed, you will see individual items such as iMovie or Keynote as “installed.” For third-party applications, however, this seems to be hit or miss.

For instance, Panic’s Transmit is installed on my system in a Tools folder contained in the Applications folder (yes, I organize my applications). The App Store correctly picked it up as installed and indicated it as such (although it remains to be seen if any updates to Transmit can be delivered via the App Store since I did not purchase, or install it, that way). However, I also have Pixelmator installed in my Tools folder, and the App Store is telling me that I can buy it for $29.99 (incidentally, looking at Pixelmator specifically, it looks like this might be intentional: the $29.99 price is introductory and for those using the current 1.x version, if you purchase Pixelmator through the App Store, you will get future 2.x upgrades, via the store, for free).

One benefit of the App Store is that there is no longer a need for licenses. Because the App Store is a “gatekeeper” of what you have installed, installing a paid application won’t require you to input a license code, as ownership will be determined by your iTunes account. This also means that if you purchase a program on one computer, but have other Macs linked to the same iTunes account, those purchases can be used on those computers as well. The Mac App Store page indicates that programs bought can be used on every Mac that you use.

Installing applications is a one-click affair and you can see the progress of the installation via the Dock. Unfortunately, the resulting application is also placed on the Dock, which is a nuisance for people like me who prefer to keep the Dock sparse. You can easily remove the icon off the Dock and find it in the Applications folder, which is where the App Store installs programs.

The Mac App Store changes the way applications are delivered to the Mac. It makes searching for and finding applications easy. There are a fair number of applications on the store right now, and expect it to fill quite rapidly over the coming months.