dannylin,
won't that be kind of hard if they never log out? And unless you force the cookies and/or sessions to die after a very short period of time... and, by doing that, you may end up annoying your more hard-core posters who drop by very often... I don't know for sure, but I don't think there's an easy way to get accurate information... but maybe there's something I'm missing...?
just my two cents worth... []/testimages/icons/smile.gif[/]
Matt