One of the tools for Flickr I noticed recently but then lacked the time to dig deeper into is FlickrCash, finally online since March 03 this year. Here´s a quick roundup.
As FlickrCash´s founder Augustine Fou puts it, using Flickr´s API "FlickrCash turns Flickr into the world´s largest stock image marketplace by helping image buyers more efficiently find images and image owners to sell them, by accepting payments for them and archiving licenses for public inspection".
To get the basic idea, you can view here for example the impressive Sunset Lightbox of FlickrCash´s developer Jesse Skinner, or watch the FlickrCash demo.
read more at StockPhotoTalk http://www.stockphototalk.com/phototalk/2007/04/flickrcash.html