Manual for creating Version 2.0 Themes

I’d like to look into developing themes for EE v2.0. Can anybody point me to any information that’s already available?

Am I correct in thinking that using EE’s “save to file system” setting is one way to start collecting files for a theme. In other words using the files from an existing EE site.

One thing I read is that everything is stored in file directories in the themes directory and that using that directory structure is how it’s done.

Thanks, Bob.