If you can find a Twitter → WordPress migration, and then import that into Micro.blog, that is probably the best way to go. Early versions of Micro.blog did have direct Twitter import, but we ended up removing the feature because so many people who used it decided later that they didn’t want their tweets in Micro.blog after all, especially if they had 10s of thousands of tweets. Perhaps it’s something we can revisit later, such as hosting a separate archive that exists apart from the blog posts.