I wrote a script to import blog posts from Movable Type to Tumblr. Download from Github.
Should be pretty straightforward. I didn’t find any such previous importers. There were actually some Perl modules which connect to Movable Type database and can do it this way, but I prefer this since it’s less error-prone and the Movable Type import file is a pretty well-established format and supported by many other packages too, all of which can now import to Tumblr through this format.
UPDATE: I found a similar Ruby importer that does one thing mine doesn’t: it also pushes the comments to Disqus. This is an interesting idea. My script not supporting comments was half engineering decision and half design decision. Engineering-wise, I didn’t think of Disqus importing, and once I saw this other importer, considered it too complex to build right now. Design-wise, I decided that comments just aren’t worth or necessary to import. So for now, just be aware that my mt2tumblr script is only good for importing posts, but not comments.