Also, one thing that needs to be done if you have yet to do it, learn HTML. I can't stress enough how many people start to learn PHP but fail because their lack of knowledge for something that is almost a requirement before hand.
But on another note, this is exactly what this website is for. Feel free to post any questions you have and we'll do our best to help out! :)
I suggest picking up a book or heading over to some PHP websites and read some tutorials. http://www.phpfreaks.com (where I work) is a very good place to pick up on PHP, with tons of tutorials, articles, code snippets, etc...
buying books from half.com could help, they have a good selection of books available, and half of them don't even cost that much. I would recommend getting learn php, apache, and mysql in 24 hours (500 pages long). It shows you how to setup apache,php, and mysql properly, and almost everything a beginner should know about php.
You may also want to try installing some of the more popular (and open source) php programs like phpbb (forums), Mambo (open source cms), php-nuke or post-nuke (other open source cms with alot of modules).
Playing around with them will give you a good feel for php and what it does but dont take anything as coding gold (especially the nukes since they are often known to be insecure).
If you have a site you should try to automate things with php and if not, consider starting one on something you like just to build your skills.