I did this last year for a site
http://www.yorkshireremovalsandlighthaulage.co.uk.
It was difficult to get my head around it at first as the main way was using scripts and cgi scripts, putting them into certain folders etc.
I figured it out eventually. No trying to redo this for another site but cant really remember how to do. After a few hours Ill get my head around it again lol
I also want to do a newsletter email subscription. That works in a simililar way!
Good luck and if i figure out how to do it ill lend a hand.
Search on google, there's tutorials on there but can get confusing!