I think this is what you are asking for:
http://www.mydomain.com/MYPHPFILE/var1/var2/
in .htaccess put this in...
<Files MYPHPFILE>
ForceType application/x-httpd-php
</Files>
in your php file you can parse out the vars this way....
$pathArray = explode('/', $_SERVER['REQUEST_URI']);
$a = $pathArray[1];
$b = $pathArray[2];
On your php file you would remove the ".php" after uploading with ftp...
[edit]
The MYPHPFILE is MYPHPFILE.php on your client...
When you upload take off the .php
In the above example you may also need to either put this in your httpd.conf or you could put this in your .htaccess file...
(I found that mine was on by default... )
AcceptPathInfo On
in .htaccess you might try to put it in your files pointer or something like this... I think the first tag is correct...
you might also try <Directory>
<Directory />
AcceptPathInfo On
</Directory>
