I use CS4 Extended for commercial work. It's the industry standard. If you are a student or faculty at a university you may be eligible for a significant discount. Check Adobe.com for details.
Welcome to the world of servers!
The quick and dirty:
Webservers are just computers running software that can serve webpages. Just like you have some sort of paint program on your computer, you could download and install a webserver on your computer also. The most common webserver is Apache...
anyfile.php is the end result of a remote php compiler producing a document for display on the web.
The php file be in a html format.
The actual php file that generates the anyfile.php will look much different from the compiled one you can see and download.