Is there an equivalent to mod_pagespeed Apache module but for IIS?
I don't believe there's a free one, but there is : http://www.aptimize.com/
update: Of course, if you're using any other automated deployment tool, you could do quite a bit by integrating commandline tools into the build batch script. HTML5 Boilerplate is probably your best practice reference there. You can also use server-side tricks like HttpCombine.ashx.