Well, it sort of depends upon what system that you are currently using to log into your site. If it is one of the supported ones see: [
www.phorum.org] , easiest way is to use the embed functions. If it is a home rolled version, it might be easier to just use the phorum login as the controlling program. You do need to keep your user table and that for phorum in sync (phorum relies upon it's user table for many functions).