Looking for a bit of input on the best way of going about doing this. Basically for a network of sites I need to have one sole login, and since I'm using XenForo felt that it would be best to use XenForo as the 'master' system, where users details are stored. What I need to be able to do is remotely register people and log them in. The registration part isnt really a problem as I can put together an addon to register people. The biggest issue will be logging them in. Ideally I'd have thought an openid style server would work. Basically openid pulling XF's user table. Is this likely the best option? To run an openid server which feeds info from the XF user table? I'm not too bothered if you have to re-login on the other sites or forums. Any ideas, suggestions, etc would be greatly appreciated and you would be rewarded with a coffee smiley! Cheers!