We'll be talking about Twitter and TweetDeck on The Roundtable tomorrow. TweetDeck (now owned by Twitter) is a great realtime consolidator of Twitter feeds and searches. Use it on your phone or personal computer to follow searches you create or common favorites (Mentions, anyone)?
TweetDeck is often what you see providing live updates at conferences or retail establishments. As with so many things social media-ish, the price is right (yes, $0), and the up-and-running investment is pretty close to that (RTFM if you're really desperate).