I'm in the process of getting a new forum up and one thing I'm planning to add is Facebook Connect for registration. I know it's available on a number of other forums but I was wondering if anybodys given it a go for snitz yet, or if anyone has experience with it generally?

Yup, I gave it a go... But since my boards are extremely modded, I can not turn it into a mod or anything... And yes, it works at classic ASP...
To start with, you might take a look at here: http://www.codeproject.com/KB/asp/classic-asp-facebookweb.aspx