The iStockphoto page is a perfect place to earn money by selling photos online. To do this, you must start by becoming a member and registration is totally free.
Then, you must send a collaboration request to the iStockphoto page explaining the types of files you want to sell (photos, illustrations, flash, video or audio). They will also send a manual that you will need to read carefully to know the most important basic details. The next step is to take an exam so as to know your level of photographic knowledge.
After the exam, send three originals to the iStockphoto page you selected. You should know that if you take seriously the opportunity offered by the iStockphoto page and prove to be a very creative person, you could become one of the many members dedicated to earning money as part time by selling photos online. 
The iStockphoto page has international partners in different countries, always ready to help you with useful tips and strategies. For this they have a forum where you can contact experienced members to ask them any questions that might arise.
Also an important point: The iStockphoto page compensates normal collaborators with a 15% commission for each file uploaded by the users download. But if, thanks to the quality of your work, you become one of the exclusive collaborators, you can get payments up to 45% for each file uploaded by the Internet users.