Starting with PHP you need to be able to set up the IIS server ( I presume you have it installed - comes with W2000 and XP Pro) to render php pages, or you need to install apache server and php library.
That is a downer for php as is not that easy to do if you haven't worked in this environment before.
Starting with ASP it is easier as the IIS is already 90% configured for you automatically. Resources are plenty as well on the web.
All this if you are going to run the pages on the local computer, but if you have a hosting package then just find out what environment you can work with.