Feels wrong posting this but with Purestorm due to close any time now it occured to me that there may be some models and photographers on this site who are unsure where to migrate to. These are the ones I know about that are still running and have UK relevance. If others know of more feel free to add. I am well aware there are strong feelings about some sites. This is not an attempt to reccommend any one over the other. I have no doubt however there will be plenty of people more than willing to fill that void.
That said it is no secret that PurplePort is by far and away the biggest and busiest. Net-Model the original for many of us but very tired and a bit of a backwater. The others I am on but really have not used them enought to have an opinion.
purpleport.com (Biggest around by far at moment. Seems to attract a lot of bile from some quarters)
Net-Model.com (Dead in the water at the moment but Brand new site under construction and looking good. Alas no eta yet)