Getting together a good development environment for PHP websites isn't that hard any more. On a Windows machine, I recommend a pretty simple approach. Install Xampp, install Eclipse PDT, install XDebug. For bonus points set up Subversion and get TortiseSVN (or, I guess, whatever other version control works for you).
I'll give a quick rundown here on how I set up a development environment on a Windows machine, I tested it as I was writing it and I don't think it took but 2 hours.