Hi.  First off, I'm a programmer with a number of years experience in mainframe database programming in DB2 and other databases.  But I'm a total noob when it comes to web development.  I know HTML and Javascript pretty well, and I've read a few books on PHP and understand it as well as any programmer learning a new language. 

I have an idea for a web site that I want to develop.  I downloaded and installed WinLAMP successfully.  I want to write a very basic PHP script that basically says "Hello World." and then build my grandiose site upon that humble beginning, i.e. stepwise refinement. 

Basic noob question coming at ya':

Where do I put my PHP script so that when I got to localhost in my browser I get my page instead of the Apache test page?