I've been developing in lot's of other languages, and never had this difficult a time setting up.
On a XPSP3 machine, I have WAMP in the root folder, with all parts installed. Then I have eclipse-helios for php installed as well.
My file path is C:\www\HelloWorld\hello.php
The follow code renders as a page fail inside eclipse and blank in my browser. In fact, "view page source" only shows me the html tags - the php lines are entirely missing.
echo 'hello world';