I'll second (or third) the recommendations for saint's book -- I just got started in this hobby (after hanging out on the sidelines for a long time), and the book is an awesome reference for building your own arcade system. It's well-written, interesting, and as comprehensive as a printed book can be. Combined with this web site, you'll be up and running in no time, and your cabinet will look great!
FWIW, I bought the book in electronic form from Amazon -- took a bit to download it, but I have it handy on my laptop whenever I need to refer to it. (And unfortunately, you have to pay full price for the electronic version -- the print version is actually significantly cheaper from Amazon. Go figure.)
-- Chris