Tools for Twitter

With bit.ly you can measure how many people click on your links, where they're from, when they clicked on them, whether others re-tweeted your message, and some pretty interesting statistics about the page you're linking to.
http://bit.ly/

TweetVolume is the Compete.com of Twitter. You can use it to track the success of your competitors on Twitter by comparing how many times you're all mentioned on Twitter. Then you can use the stats from the above tools to increase your volume.
http://www.tweetvolume.com/

Twitter-Friends gives you 19 metrics about your own usage such as Twitter Rank, Loyalty (Stickiness), Conversational Rank and other interesting metrics. It comes with all kinds of pretty graphics for those "convince the boss that Twitter is useful" presentations.
http://twitter-friends.com/

Here are some more you can check out:

http://www.tr.im
http://snipr.com/
http://TweetLater.com
http://TweetDeck.com
http://bit.ly
http://tr.im
http://snipr.com
http://twitterjobsearch.com

Below are Firefox Addons:
Twitbin : https://addons.mozilla.org/en-US/firefox/addon/7631
Twitbin is a firefox extension that allows you to keep up with all of your Twitter conversations right from your browser sidebar. Send messages, receive messages, share links, and more from Twitbin, the best twitter addon for firefox out there.

Twitter Fox: https://addons.mozilla.org/en-US/firefox/addon/5081
TwitterFox is a Firefox extension that notifies you of your friends' status on Twitter.

Hope you like this post all about twitter tools, let me know if you know other tools in your comments, thanks.