I got an enquiry from someone wanting to use one of my flickr photos on their website. It got me thinking about the licensing on my photos. I deliberately chose to reserve all my copyright rights when I put them up there, but that enquiry has prompted me to share them under a Creative Commons license, known as "Creative Commons Attribution-Non-Commercial-Share Alike 2.0".
That person will still have to buy the right to use it, if they want, but for non-commerical uses you can use them.
I'm a big fan of Creative Commons as a consumer - I sometimes get CC photos from flickr, or download CC music from magnatune.com.