MSNBC had a great article on the power of Twitter during this election. The tips they list below are good ones, and even if you don’t have an account, just seeing the livestream on election.twitter.com is AMAZING!

Use Twitter like a pro on Election Day
Register for an account at Twitter.com. Choose a username you like; part of the fun of Twitter is people publicly responding to your tweets and vice-versa. If your username is TwitterNewbie, other twitterers will reply to you by starting their tweets with “@TwitterNewbie.”
Cast your vote for the president in Twitter’s mock election, twitvote.twitmarks.com.
Check out and participate in election.twitter.com, a constantly updated stream of what people are saying about politics on Twitter. Hot topics are highlighted at the top of the page.
If you have voting problems, head over to twittervotereport.com, a site that compiles tweets of people sharing their voting experiences and suggesting resources.