I've changed my background color to a dark blue and want to change the body and modules text color to a lighter color. How do I do that in the style sheet editor? Also, is there a document that explains all the style sheet editor options.

Normally, you would edit the skin.css file. The stylesheet editor allows you to edit portal.css

If you stick to skin.css, you will subject yourself to less confusion at the beginning.

You can get a pretty good handle on this by viewing the (rather large) collection of skinning tutorials that we have. I also recommend the introductory book by Hammond and Renner. While it's doesn't concentrate on skins, it will give you a feed for how things play together. There are several other books on DotNetNuke skins - one by Wittenkeller and one by Hay. And, there are occasional other free webinars offered by DotNetNuke Corp.