Of course everyone is different, but I see two main ways to learn PHP.
a)Find a script and go through it. - This is how I learned. I took the phpBB forums, and played.

(Heck, all i knew before starting it was the very basics of HTML). However, I did have the "programming concept" before hand because I knew VB.
b)Buy a book. There are quite a few good books out there. This might help a little more if you don't really have a clue as to what a variable is, if .. then, do .. while, and other basic programming concepts.
jack
ps:Ask others who know php a question you get stuck on something.

.. I did, and I can't thank my "tutor" enough.
