I've got the beginning of a XMLRPC Blogger API implementation now, for v0.5.2. So far, b2's custom xmlrpc server recognizes the methods blogger.newPost, editPost, deletePost, and getUsersBlogs.
This is enough to already post with BlogBuddy, and some other apps.

b2 will ship with the minimum required for XMLRPC, which is the xmlrpc php classes, a xmlrpc server file, and a xmlrpc demo client that would allow you to test the newPost, editPost, and deletePost methods, and show you how xmlrpc calls work.
(Now if only Ev updated his blogger API pages instead of giving updates on the sole BloggerDev mailing-list, it would make my day.)


UPDATE: Now b2 deals with blogger.getUserInfo, getPost, and getRecentPosts. I think there's only the xmlrpc template calls left to implement, and those should be very straightforward.

UPDATE2: Implemented getTemplate and setTemplate, and this means I'm done with the Blogger API. Started coding some b2-specific methods, like b2.getCategories etc; hopefully someone will make a xmlrpc client that supports category and title, or a standard API will come with these, in such case we'd switch to it right away.