Free monitoring software?

I need something that can tell me what time someone logged on to my computer. In other words, software that keeps track of who goes on when. I thought I could find something really simple and cheap, but so far no luck.

Thanks!

Took me 5 seconds to find this with Google:

http://chemware.co.nz/usrlog.htm

Seems to have what you asked for and it's free.

I'm surprised XP doesn't let you do this natively, TBH.

Wow, thanks a bunch Mustang. Didn't think of searching for "user logger".

You can enable auditing on Windows 2000/XP... It's build in. any logon / logoff will then be noted in the EventViewer.