Welcome to WebmasterWorld Guest from 126.96.36.199
WordPress And Google: Avoiding Duplicate Content Issues [webmasterworld.com]
So if your hosting soltuion doesn't/can't/won't support isapi_rewrite then WordPress on IIS is a bad choice if you're hoping for decent search engine listings. You're better off finding a company that's familiar with WordPress on Linux/Apache. It will most likely be cheaper too.