I have just noticed that the old URL (bikeforums.com) is still listed at yahoo. Should that have been updated?

Yes / No.

Yes, the domain isnt really being used right now, this should change in the next month or so.

No, If i ask Yahoo to move it to the .net, they may drop the site totaly, they provide a handfull of the traffic here, id rather not risk that right now, and i'll use the .com soon :)