We have a 2003 environment with majority of PC's still being xp. I have been updating servers and PC's to 2008 and 7. One thing I have noticed when a users domain password is getting close to expire the new PC's and citrix sessions running on 2008, the end user doesn't get the warning that there password is going to expire and would they like to change it. For all the xp and 2003 boxes the warning starts at 14 days. The xp and 7 pc's are in the same OU in AD so Im not sure why they do not get the warning.