Just got told about this on the blug mailing list, so thought I'd pass it on: http://www.opensourc3.org/
Is fairly advert heavy in the pdf, but nothing that can't be easily skipped past, looks like issue one is a brief introduction, I'm hoping issue two gets a little more indepth.
Anyways - not a completely bad read - worth having a quick squint at.
Cheers,