Tools for Monitoring and Managing Social Media

Backtype helps you find, follow and share references to your business, brand or identity online:
http://www.backtype.com/

Trackur helps you monitor your buzz, protect your reputation and listen to your customers:
http://www.trackur.com/

Tweetdeck can help you manage your Twitter account(s), track #hashtags, use Twitter like a chat and even see trends within your own account:
http://tweetdeck.com/beta/

So can Nambu:
http://nambu.com/

With Tweetlater, you can set up a Twitter campaign and pre-schedule the release of your tweets:
http://www.tweetlater.com/