How, on a multi user machine running windows 98, can I retrieve the current users information?

All I'm trying to do is get the login name of the user that's currently logged in.

I looked around about the registry, but I didn't find any documentation about it there (just about the registered user and registered organization).

Is that information in the registry, and if so, is it the same on 98, 2000 and NT?

Thanks.

Jeremy