Importing Content from Another Platform or WordPress Blog
It is possible to import your blog content from a variety of other blogging platforms, including Blogger, Israblog, LiveJournal, Movable Type, Posterous, Storylane, Tumblr, Typepad, WordPress, Xanga, and Yahoo! 360. To reach the import screen, log in to WordPress.com, add /wp-admin to the end of your home page URL, then go to Tools → Import. Choose your previous platform and follow the instructions.
You can also easily import content here from another WordPress.com or WordPress.org blog or web site (choose the WordPress option).
Don’t See a Specific Importer for Your Blog’s Service?
For SquareSpace imports, make sure you’ve made an xml export (and confirm the file has the .xml extension at the end), and use the WordPress importer from your Tools>Import screen.
If we do not have an importing tool for your particular platform, you will need to try and convert it into one of the accepted formats so that you can use the proper importer. This means you first convert your blog to one of the services mentioned above (such as Blogger), and then import your blog from Blogger to WordPress.com.