Microsoft just put up their Windows Live Messenger app on iTunes. It’s free, so if you need an IM app for the Windows Live network, you can get it here. There really shouldn’t be anything more to it past that, but if you need the details (and you should; just because it’s free there’s no reason to download it if you don’t use it, right?), Windows Live can also link up with Yahoo!, letting you talk to YM-based contacts, and it also features status updates from social networking sites such as Facebook, Flickr and MySpace if you need to stay “updated” while chatting on IM, and allows for photo uploads and sharing. Windows Live Messenger for iPhone is compatible with any iPhone (including the new iPhone 4), iPod touch, and iPad running iOS 3 or later.