If you want to learn a programming language, most people advise you start out with Learning Perl, the inimitable classic by Randal Schwartz.  And I agree that it is a pretty good book, which I have referred to many people as a great starting place.

But personally, I learned more about programming from Programming PHP (a.k.a. "the cuckoo book" as per the animal on the cover, not for any sanity claims) than I did from Learning Perl.  This may be partly because I'm a visual person, with a love for website design, and I have an easier time picturing how I might use PHP than I do a command line tool like Perl.  (Sure you can write web pages in Perl, but why would you want to?)
Read more about "Programming PHP" by Rasmus Lerdorf and Kevin Tatroe