Sprite Sheets for Web Development

I'm currently working on a new site. I'm just a few pages deep and they all use s. I was thinking about it and decided to look into using a sprite sheet for all of the button images and such and then just using CSS to render the appropriate images. I wanted to see what everyone thought about this. Is it worth the effort? How does it affect SEO, specifically ALTs for s. Is there anything else that I should be aware of?

Thanks in advance!