I'd be very surprised if they created anything for IIS. Most people would like to see the back of that crap, not encourage its use.
Anyhows, you don't really need any module. All that will be doing is optimisations on content, (optimising images, merging and minifying JS and CSS files), sending proper caching/expires headers for fairly static content, putting CSS and JS script links in the head and foot areas respectively etc. There's nothing it will do which you can't do separately. Install Firefox with the Page-speed and Yslow addons and you'll soon see the types of thing it will be doing, because it will tally up generally to the suggestions given from those tools.
Basically, optimise and cache content is what it primarily boils down to.
Edit: If you read these pages:
that'll give you a good indication of what you need do to achieve the same type of functionality. Personally, from what I've seen of page-speed so far, you'd be better off implementing your own methods anyhow. Last I checked, for example, their html compacting "suggestions" broke strict doctypes with a vengeance. I think I even filed a bug report over that one, (not with their Apache plugin but with the user side tools).