There's a book here that looks good - published by Packt - http://www.packtpub.com/game-jam-survival-guide/book ... its by Christer Kaitila, a game developer with 17-years experience. I don't think its got any technical information. I haven't read it myself, but these headings from the table of contents look like good advice...

- Go with what you know

- Don't try a new language

- Don't worry about making it beautiful!

- Keep It Simple, Stupid!

- No-art (rectangles) gameplay proof-of-concept

- Heinous hacks and ugly code are A-OK.