Carnage4Life has some info about the MetaWeblog APIs for MSN spaces. This allows you to post to your Spaces blog using many different tools, like W.Bloggar, Blogjet (which is fast becomming my favourite blogging tool!), Ecto ,Zoundry Qumana, Onfolio, Elicit ,PostXING, Pocket Blogger and Diarist – PocketPC. Very cool stuff! There are also tips on how to post to Spaces using W.Blogger here and BlogJet here.