If you’re getting:

HTTP Error 404.3 - Not Found

The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.

This is because IIS7 isn’t setup to serve out WCF svc files by default. Quick fix is this:

%windir%\Microsoft.NET\Framework\v3.0\Windows Communication Foundation\ServiceModelReg.exe -r -y

Thank god for the internet and David Sandor.