Not sure if this is something already known, but I came across this section in the Goodwrench site:
http://www.goodwrench.com/gmgoodwrenchjsp/gmspo/techrepair_index.jsp
It links to free downloadable PDFs that summarize body and chassis structure, with a focus on collision repair. Lots of easy-to-read diagrams whether you're trying to work on the "written off" car you bought back from your insurance company, or just trying to see how much work it takes to replace a rusty rail or member. A Cavalier and Sunfire guide is available, as well as ones for loads of other GM cars.
Shop Manuals, Brochures:
www.kenmcgeeautobooks.com
