According to Neowin's sources, Windows Live Messenger for iPhone will officially be previewed by Microsoft later today, but will not ship its public beta until June, with a limited private beta expected in May.
Features gleaned from the screen shots include photo sharing, chat and a social stream for users.
Of course, MSN Messenger has been supported on the iPhone since the unveiling of the app store via thrid party apps. Some of the popular ones include Nimbuzz (free), IM+ ($9.99), and Trillian ($4.99).
Stay tuned for the official announcement later today and click on over to Neowin to see all the screen shots.