As well as MSN releasing their Search API's, MSN's own start.com has also released an API, which I think is built with the ATLAS framework that Microsoft are trying to get ready for the release of ASP.net v2.
Why do I say ATLAS? because over on
http://start.com/developer/default.htm, you will see a link to an ATLAS runtime overview
http://start.com/developer/atlasruntime.aspx.
All of this requires a bit more investigating :) It is really interesting because it appears that it is all about creating components called Gadgets that Javascript RSS consumers.... I think. All of which have to be hosted on your own server. I don't know if it has to be IIS specific though.
One thing I have noticed from the "Getting Started" is that you need to enable cross domain data sources in Internet Explorer, whichI have already talked about in an earlier post [
here].
I need to look in to this too :) I am going to have a busy weekend!