Hey,
Back in the day of PHP v4 I was also having the same problem getting started.
I would recommend going to the local library and checking out a few PHP books, more specifically O'Reilly based books that focus on PHP v5. Also, check out the following URL's:
PHP Manual intro:
http://us3.php.net/manual/en/introduction.php
Nice little intro:
http://www.devshed.com/c/a/PHP/An-Introduction-to-PHP/
And the one URL which will always save you, the PHP manual:
http://us3.php.net/manual/en/index.php
Welcome to PHP