I am not quite sure which version is the first to allow this, but the latest on the official site should let you : http://download.live.com/?sku=messenger .
I am using version 2009 (Build 14.0.8.xxxx) and it works perfectly.
Multiple Pc - by TenturaLover on 02-20-2010 at 01:59 AM RE: Multiple Pc - by albert on 02-20-2010 at 02:49 AM RE: Multiple Pc - by djdannyp on 02-20-2010 at 11:29 AM RE: Multiple Pc - by TenturaLover on 02-20-2010 at 04:11 PM RE: Multiple Pc - by djdannyp on 02-20-2010 at 05:38 PM
/ 
