To get PDT running under Vista 64 with IIS 7 (rather than apache), I
followed the instructions given at http://www.brucebarrera.com/how-to-install-php-5-and-mysql-on-iis-7-and-windows-vista-windows-7/
Unfortunately, there was no php5isapi.dll included in the eclipse package
so I got it from the Zend php package and moved it into the folder with
the other php stuff in Eclipse.
I still had a problem because I was under vista 64 but fortunately I found
an answer at http://www.hanselman.com/blog/HTTPError40417PHPOnIIS7Under64bitVista.aspx
I guess my question is -- is there a better way to do this that doesn't
require getting the extra file (php5isapi.dll) from the full php stuff?