Go to MyBO (http://my.barackobama.com/), log in (or create a log-in), and scroll down a bit -- you'll see the big blue square for "Massachusetts Special Election -- Make Calls Now". Through that, you can phone bank from wherever you are. I believe you'll then get some basic instructions, followed by numbers for Massachusetts Democrats and a basic script. The message is probably just as simple as "hi, I'm a concerned volunteer and I want to make sure you vote today!".

I confess I'm a bad Democrat because I haven't done this today. I've instead been reading up on labor policy and writing Joe Hoeffel's labor statement, making it kick-ass so we can get key major endorsements ... which is, like, really important and all, but still feels small when compared to the Massachusetts election.