like cam said sitepoint is a good place to start.
I'm reading a book by them on building a cms combining php and xml. Dont know fuck all about programming but the book guides you through the whole process. Once completed you can use the end result wherever you like - at least thats the big sell.
I've had 2 potential clients ask for the ability to change things on their sites and rather than give them a pirate copy of Contribute I thought I'd bite the bullet and get my head stuck into some backend stuff.
Hey,if I can do it anyone can... I'll let you know if I can!