First you need to learn the basics:
The best way to learn is to install all the tools on your home system and dive in. You can find tutorials to help you set up Apache/PhP/MySql such as this one for windows systems (I have not actually used these articles, but at least some people found them helpful):
http://www.devarticles.com/content.php?articleId=202&page=1
http://robouk.mchost.com/tuts/tutorial.php?tutorial=server1
You can also find packages that wrap and install the needed applications. Some are more updated than others, some give you more or less control than you might want, some might have bug issues. Most of them have their own forums. You might find it pays to check them out before installing if you go this route.
On my home system (W98) I opted to install EasyPHP (some bugs, errors in French). It was not the result of any research, it just happened to be the first 'all in one' package I encountered. I have since heard about some other packages but I have not tried them. I have heard that FoxServ is the most up to date, PhpTriad may have discontinued developement, and I have not heard much of anything about PhpDev.
http://easyphp.org/ (EasyPhp for windows)
http://www.foxserv.net/portal.php (FoxServ windows or linux)
http://sourceforge.net/projects/phptriad/ (PhpTriad windows)
http://firepages.com.au/ (PhpDev windows)
A forum such as this comes in very handy when addressing the individual issues and confusions you may run into. There is also a wealth of information on the net. A google search with keywords like; PHP MYSQL BEGINNER TUTORIAL; will return thousands of pages. Then there are is the basic arsenal:
There is the php manual, which contains within its pages all the facts and functions at your disposal, which is also available for download: It also contains a beginning tutorial and is available in several languages.
http://www.php.net/manual/en/
http://www.php.net/manual/en/tutorial.php
If you don't know SQL you should really search out some SQL tutorials. (maybe http://www.sqlcourse.com ) Even if you DO know SQL you need to familiarize yourself with MySql. Their documentation also has a basic tutorial that is based on working from the shell which might seem confusing if you are in PHP mode, but if you are new to SQL installing it locally and working from the shell could turn out to be an invaluable way to gain a level of understanding that will pay for itself many times over:
http://www.mysql.com/doc/en/index.html
There are tons of tutorial all over the net, many of which can be very helpful. I found my introduction to PHP/MySql at Webmonkey.
http://hotwired.lycos.com/webmonkey/programming/php/
http://hotwired.lycos.com/webmonkey/programming/php/tutorials/tutorial4.html