Noob question: what's the deal with PHP? Is it important to games?
I'll try and give the Cliff Notes answer for this -
First off I don't know what ryackov meant when he said not many hosts support PHP, I've never seen a host that doesn't; there's the odd one the wont let you use some PHP functions, but these are just guys in their garage; any decent webhost has PHP.
As to what PHP is, well there's two types of websites, static and dynamic; static sites are exclusively written in HTML, and dynamic sites use PHP. The most common use of PHP is to either retrieve or submit information to a database server; and the most prevalent example of this e-mail forms.
As for whether you need it, you will, but I wouldn't bother looking for it, everywhere will offer it.