I can highly recommend Adult Folio. Writing as a photographer it is a great place to arrange castings with a wide variety of models and also a good platform to show case your work. Very importantly the site is easy to use and any queries are swiftly dealt with.

Only been on here just over a year and have had about 9 shoots so far with some great models. Resulting in some awesome shots. Looking forward to my next shoot booked next month, and more great images.