While Windows Live Messenger may not be the most popular instant messaging service for Mac users, it still deserves a place in the App Store, right? Microsoft seems to agree, as it launched an official, free Windows Live Messenger app [link opens in iTunes] for the iPhone and iPod touch. (The app will also run on the iPad, though it's not optimized for that device.)

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Windows Live Messenger lets you chat with your Windows Live and Y! Messenger buddies, and keep up with them through social networks like Facebook, Flickr, YouTube, and MySpace. You can also view chat history and access your Hotmail account.

Oddly enough, the app has been released without support for iOS 4's new multitasking ability, a function that is especially useful for chat apps. Windows Live Messenger does, however, enable push notifications, so IMs you receive can still pop up even when the app isn't running.