I do not have a site to recommend, but thought that I would add this. Keep in mind that not all stock photography is aimed at advertising ( billboards, magazine ads etc. ). There is a market for editorial photography ( encyclopedias, trade papers, magazines, websites. ). Model releases are a must have for advertising, and usually not needed for editorial stock. I am looking to try to get into the stock photo market soon but need to get enough photos together. My advice would be to find something that you can specialize in. For instance, if you have a dayjob that allows you access to things that the average photographer isn't around ( law enforcement, doctor, nurse, construction, manufacturing, mining etc. ) then use that to your advantage. The more you specialize, the more chance you have of becoming that "go to" guy for a stock agency when they need specific types of photos. Especially if you have knowledge in that field and can add very detailed captions. A common misconception is that the more varied and large your stockfile is, the more you will sell.