I posted a link earlier about exporting content from WP to Tumblr. Searched and found this, which is a tedious way since I have 12Mb of data, and there is also PHP script here which I think is the same as the one I posted earlier. There is another one here which is a WordPress plugin. I don't know Python but if you do you could try this one. There is even a command line tool in Ruby, if you know the language, head over here.