The Live Writer beta has been updated (yay!).
It now supports the blogger beta, so I guess I'll go download it now and see what the other changes are like.
Many thanks go to the writer team for listening to the community :-)
Update: Blogger changed their own beta and caused the Live Writer connect to fail. There's a post at http://jcheng.wordpress.com/2006/09/28/blogger-beta-workaround to explain how to fix this problem.
(P.S. The update was written in Live Writer to prove it all works now).