This site was featured in the last issue of Popular Photography. It's called ShutterStock.
You can create a free account and upload your photographs free of charge. Businesses or casual viewers who have a paid plan with the company are allowed to download your photos. You get paid 20 cents per download for each photo. You have 1 photo up that gets downloaded 100 times a month, you have get paid $20.
Could be an easy way for some of you photography enthusiasts to make an extra buck for a new lens or two