Microsoft and Apple came together today to release the official Windows Live Messenger app for iPhones and iPod Touches.  Available now on iTunes, the app allows much of the same functionality available with Windows Live Messenger on your PC.  Users can chat with multiple friends, use emoticons, "nudge" their inactive friends, view photos and links in IMs, and receive push notifications of new chats.  Also available is the ability to view updates from their Messenger friends on social networks like Facebook.  Hotmail support is baked into the app, with the ability to check your mail and compose messages, as well.  Finally, the app works with Y! Messenger and is fully compatible with the recently-released iOS 4.

While it may not feature compatibility with every single chat service out there, the Windows Live Messenger app looks like a solid way to keep in touch with your friends.  The ability to view updates from Messenger friends on various social networking sites like Facebook and MySpace is definitely a nice bonus.  With push notifications, Hotmail support, and the ability to view photos and links in the app, Windows Live Messenger is certainly one of the more fully-featured messaging applications on the App Store.  If you have an iPod Touch or iPhone, you can download Windows Live Messenger right here.