Today Microsoft has officially launched Windows Live Messenger for iPhone and iPod Touch. Using Windows Live Messenger you can instant message your friends, view and comment on their status updates and photos.
Windows Live Messenger features, as it says on the iTunes description
Chat: Instant message with your Windows Live Messenger and Y! Messenger contacts on the go so you’re always connected to the people that matter most. You can even receive IM notifications when your app is closed so you never miss a message.
Social: Windows Live Messenger gives you one place to view the updates your Messenger friends are sharing from social networks like Facebook, Flickr, MySpace and more, helping you cut through the clutter on the go.
Photos: Upload photos right from your phone to share your favorite moments with the people that matter most. Create albums, add captions, and let your friends and family comment on your photos.
Hotmail: Access your Hotmail account without leaving the app to read, reply to, and compose emails. Get email notifications within the application
so you know when you have new messages.