We have just completed a redesign of our website and it is now much more google friendly.
In the redesign process we have had to rename a few of our urls.

We haven't launched the site yet as we want to make sure that we don't loose the top rankings we are currently reaching with google. We have read that the best way to ensure the cleanest transfer from our old site to the new one is to redirect the old urls to the relevant new ones using 301 permanent redirections with the .htacess file.

We have however run in to a huge hiccup. On testing our .htaccess file we discovered that it is not compatible with Microsoft servers as they don't run apache according to our web host.

Does anyone know if this is true? What is the simplest alternative to run 301 redirects on our server?

Our host mentioned something about IIS. I can't find any info about this though.

Thanks in advanced.