If you don't have any programming background, then you may want to start with some introductory programming tutorials. Also find what you can on debugging because someone who can write some code but doesn't know what to do when it doesn't work is a lost cause as a programmer.
Once you have a handle on the basics, then you can find some PHP tutorials and examples (you can start with W3Schools or just do an internet search). There is lots of sample code and open source programs out there so download some simple ones, get them to run then try making some simple changes.
I also recommend that you download the php manual. The layout of the index page keeps being changed, which is confusing, but if you have a copy of your own, you will get familiar with where to find stuff.
I'd recommend getting few books too. They are generally peer-reviewed and written by experts in the field. Web tutorials can be written by any old idiot.
Wrox, O'Reilly and Apress are good publishers of quality books.