Does Samba work with windows 2000 and XP?

[Dave Martini 1]

I was wondering if Samba works with 2000 and XP clients
and also if it authenticates the usernames to active directory windows
2000 and 2003 servers?

We're using Totalnet Advanced Server currently and I'm wondering
if Samba will do the same thing that Totalnet does minus the Appletalk
Realm portion. 

Thanks much.
Dave Martini
LLNL