Most businesses are starting to participate in Twitter to promote their products or services. We all know we can get to Twitter by using, Twitter.com, but there are applications that are out there to make the Twitter experience even more easier.
Tweetdeck is a free desktop application that enables you to see all of the tweets of Twitter users you follow, replies to you and direct messages. That's the basic way of using it. But if you want to monitor specific keywords, a user or hashtags, you can track that too. Using Tweetdeck is a great way to monitor your brand, as well as your competitors. I think its really easy to use, and you can even send updates to your Facebook account as well.
Another desktop Twitter app that is also popular is Seesmic Desktop, which has similar features as Tweetdeck, but Seesmic Desktop allows you to manage more than one Twitter account, if you do have a personal Twitter account and a business or brand name Twitter account. It also allows you to organize your Twitter followers in groups and by Search query. Seesmic Desktop is also free to download and use.