At Searchification back in September Microsoft demoed a Webmaster portal designed to run side-by-side with the new Live Search, and it is now available in beta. The SEO blogs I've seen posting on this have mentioned that it is a private beta as they received a specific email invite, however for those wanting to try it out I managed to log straight in at http://webmaster.live.com
The portal first asks you to setup a profile for the website you want to analyse, which unsurprisingly includes a verification step; you can either upload an xml file or insert a meta tag. The service seems to pick up the meta tag update immediately, which meant we could dive right in.
The summary page is basic but functional, showing when your site was last crawled (or if your site is blocked) and how many pages are included in the Live Search index. For webmasters experiencing problems with a site, this should be your first port of call. The domain rank graphic is a nice touch, though breaking it down into five levels seems insufficient for really being able to gauge performance. For comparison, Google Pagerank goes upto 10, and we're rated 6, how this equates to a Live Search 5/5 we don't know
Additionally there is a keyword analysis tool, showing how you would perform on Live Search for certain search queries. Again the lack of granularity in the rating system hurts here, to improve your SEO you have to do badly at something! To wrap it all off there is an inbound and outbound link analysis, which if you run a proper website (ie not a blog) will help see where you site is being promoted.
Windows Live Search Webmaster