In reply to Jeff Chandler.

You can do that with ITTT.com.

And you could use an archiving tool like Ozh's one to pull them into a local install, then export to XML, them import that to WordPress.com to get your old tweets uploaded as well.

ITTT.com doesn't handle tags, so I ended up writing a short script to handle that for me. I don't have it automated yet though, so I have to go manually run it sporadically. ITTT.com also adds it's own tag for itself, so I have to remove those too (via the same script I use to generate the other tags).