the best is always to make a written model release; usually the photographer gets all rights on the images (personal rights, copyright etc.). for non commercial issues both are free to use the images on websites, sedcards, contests etc. for contests there may be a share of the model in the won prize (35%). any commercial use has to be agreed separately (model share for portraits 30%, nudes 50%). in any case it's better to have a written agreement.

Gerald