I'm working on importing my blog from Wordpress.com. Blogger.com apparently will let me use AdSense even with free hosting, and I should get to know more about AdSense and about the Blogger platform as well, as a Googler.
I used the Wordpress.com export feature to create an XML file, and used the http://wordpress2blogger.appspot.com/ tool to convert it, as I was under the 1 MB size limit. The code behind that converter is evidently at http://code.google.com/p/google-blog-converters-appengine/.
That tool plus Safari saved the result with an .xml.html extension, which resulted in a Blogger error code of "bX-uroqxm" when importing. Removing the extraneous .html allowed the Blogger import to mostly succeed.
It does not re-map my Wordpress author identity to my Blogger profile. It also does a pretty poor job importing my source-code formatted content. So I'll be slowly publishing the old posts, tweaking that kind of thing as I go.