I still prefer Texture Packer (http://www.codeandweb.com/texturepacker http://www.codeandweb.com/texturepacker) - it has a free mode, but the best sprites will

I still prefer Texture Packer (http://www.codeandweb.com/texturepacker http://www.codeandweb.com/texturepacker) - it has a free mode, but the best sprites will be made with the paid version. While it seems to be targeted towards mobile and games, but works very well for CSS sprites also. Does a nice job generating both the CSS and the Sprite image. Really simplifies the ability to have multiple developers working on a single sprite.