You can if you use Windows Live Messenger and join the Yahoo interrop beta
(http://ideas.live.com) and your contacts need the latest Yahoo Messenger as well.
Otherwise with just Windows Messenger the answer is no with the exception if you're
connecting through a Live Communications Server with a Public IM agreement (if you have to
ask, you're probably not).
--
Jonathan Kay
Microsoft MVP - Windows Live Messenger/MSN Messenger/Windows Messenger
Associate Expert http://www.microsoft.com/windowsxp/expertzone/
Messenger Resources - http://messenger.jonathankay.com
All posts unless otherwise specified are (c) 2006 Jonathan Kay.
You *must* contact me for redistribution rights.