Popular blog Game From Scratch has uploaded a video giving developers a look at a web-based product for creating sprites called Universal LPC Sprite Sheet Character Generator. Mike describes it as "quick and dirty, but incredibly powerful."
The program allows you to create a number of sprites in a variety of poses, animations and perspectives. While he admits the UI for the site could use some touching up, this could be a useful resource for developers who either may not be artistically inclined or just looking for a quick way to generate sprites.
More can be read on this program here, and you can check out the generator here.