If you are have some c programming experience, then php should be easy to pick up.
This should get you started writing some intense php code in a day or two.
1. Go to the IBM website, you may need to register.
2. Search for "Learning PHP" tutorial. It is a series of 3 tutorials
Learning PHP, Part 1: Register for an account, upload files for approval, and view...
Learning PHP, Part 2: Upload files and use XML to store and display file information
Learning PHP, Part 3: Authentication, objects, exceptions, and streaming
They are very short, you can do each part in about an hour, and you will have a thorough understanding. I only did the first two and created a very dynamic site from scratch.
For references as you develop, you should use these sites.
www.php.net/
www.w3schools.com/php/
The ibm tutorials are geared to the complete beginner. So if you have ever programmed, they will be even easier. This will get you writing php code in a day.
The first tutorial says some html knowledge could be useful. You really don't need it to do all the tutorials, but it shouldn't hurt to pick up the html basics.
Do it at
www.w3schools.com/html/
Do an hour of the intro tutorial and you will have more than what is required in the IBM php tutorial
Don't look at any books before you try this method. Thank me later. 4 hours at most.