NeoWin are reporting that M$ have already updated their Windows Messenger from v4.5.0120 to v4.5.0121.

This update is across the board, for Windows XP as well as Windows 9x/NT/2000 versions. Send instant messages with cool, new emoticons, call anywhere in the world from your computer, see when someone's typing, page a contact's mobile phone, send pictures and music to your friends, and much more.

Download: Messenger for Windows

Windows Messenger v4.5.0121 English

Windows Messenger v4.5.0121 German

Download: Messenger for Windows XP

Windows Messenger v4.5.0121 XP English

Windows Messenger v4.5.0121 XP German

Download: Messenger for Mac