Create session data for guests on external site

[lightdarkness]

Hi there. I'm trying to create a row in vb_sessions for logged out users, when they visit my main home page (Not the forums), so that I can have an accurate count of how many guests are online.

Is there a snippit of code I can grab that will check to see if they already have a guest session, if not... create one? Any help would be appreciated. Thanks.