That's because you're reading "For Dummies" books.
I've never met a developer who had a "For Dummies" book in his office.
Regardless, ncollette isn't learning PHP/MySQL. Of course, there's a ton of great, free online resources for both languages - not the least of which is php.net.
And a lot of books that I guarantee are superior to anything in the "For Dummies" line.