I would say the best way to really start learning php is to install php, apache, and mysql on your own computer and run a small web server for yourself just to learn php and mysql. Having it on your own computer will really allow you to explore all the settings of php, and you won't have to deal with the hassel of uploading your files to a server.
I would recommend using this install package to get everything going: (For windows users)
http://hotscripts.com/Detailed/31482.html
It will probably install more than you need, but you will have enough to get started.
Then I would start reading tutorials to learn the basics. This is the first one I read:
http://webmonkey.wired.com/webmonkey...tw=programming
It is a little outdated, but will help you get started and is very easy to understand.
After you have grasped basic knowledge of php variables, control statements, loops... I would then start using the php manual (
http://www.php.net/manual/en/) to discover all the great functions there are and then start to learn databases. Once you have the basics learning the rest is not that bad and actually a lot of fun.
Php is a very useful language for creating web applications. Many people love it, because its ease of use and wide array of functions. Once you learn it, you will find so many uses for it.
Hope you enjoy php and if you need any help post back!
Chris