Network Login On XP

We have just got a new pc with win xp professional on it..we are use to win 2000 pro. and cannot figure out to get the xp to let you logon to the network like win 2000…is there a way to have it set you up to login when you boot up and it be logging you into your network? this is different obviously to win 2k or so it seems..please advise on how to get xp to logon to the existing network when you actually boot up and logon…thanks ser