Twitter the microblogging tool has become a macro-tool for events since event planners need to be up to date with trends, audience needs and feedback, buzz and much more. So here we go with a list of twitter tools planners may use pre, during and post events.

To Manage accounts

1. tweetdeck TweetDeck is your personal browser for staying in touch with what’s happening now, connecting you with your contacts across Twitter, Facebook and more.
2. twhirl Connects you to different accounts such as twitter, friendfeed; it has a cross-post function to Facebook and LinkedIn.
3. HootSuite It's a complete and excellent tool to manage different twitter accounts, track statistics, brand monitoring, schedule tweets and more.
4. Socialoomph Used to be tweetlater.com now with a new name and much more services.
5. Seesmic  A desktop client to manage your lifestream from Facebook & multiple Twitter accounts.

To Plan

1. Twitter hawk Is a real time targeting marketing engine that will find people talking on twitter now by your chosen topic and location.
2. Micro.vois.com Are you looking for freelance services like web developers, graphics, writers, etc. to help you with your event? This can help.
3. Xobni twitter in outlook saves you time finding e-mails, conversations, contact info & attachments. It also has e-mail analytics and soon you'll be able to use it in your mobile.
4. TwitterCal This is the Twitter tool that enables users to add events to their Google calendar directly from Twitter. 
5. Taweet Love this tool, it's a beta and a free Twitter application and social calendar that allows people and businesses to streamline promotional scheduling for events, product launches, life casting and more! 
6. Polls.tw The easiest way to make polls for twitter, need any feedback from your audience?

7. TweetTeleVision (TTV) Are you really busy doing some stuff for your event away from the computer, but reachable to watch and don't want to miss a thing? Just clap!

8. Amap.to Show a map and give directions to your events with a link. 
9. tweetmypc Lets you shutdown, restart, Log off and do lots more on your windows PC. All remotely via Twitter!
10. tweetmymac Lets you get screenshots, iSight snapshots, and your IP address from your Mac just by sending a direct message to your specially setup Mac controlling account. You can start torrents remotely, shutdown your Mac and more.
11. tweet.IM  Are all your e-mail accounts in Gmail? This tool enables you to use micro-blogging platforms like Twitter from Google talk or Jabber.
12. Schmap.it Is a platform to share events on Twitter.
13. It's on  Spread the word about your event or find events.

14. Tweet Scenes Is a Twitter tool that creates customized backgrounds for your company/brand (not free).

15. TwitMesh Features different tools like Twitter Groups, Twitter Invitations, Twitter IM and Twitter Search.

16. Tweetvite Makes it easy to create invitations for events you're hosting or to find local Tweetups.
17. TweetMeUp The easiest way to organize Tweetups!
18. Twtvite Is an event management tool that helps you organize Tweetups and make meaningful connections through social media.
19. Twibbon Is the easiest way to promote awareness about your cause through Twitter. 
20. TwitCause Helps nonprofits to get discovered on Twitter and enables passionate people to support causes they care about.
21. TwitComings  Provides you with real-time information about your favorite events: Concerts & Live Music, Conferences, Festivals, Technology and more.
22. Twaller To share ideas and tips while traveling.
23. TwitDone Personal twitter space for getting things done.
24. twtTRIP Are you having an event out of town, want to share your travel plans and meet other travelers? This can make your travel an adventure.
25. Xpenser Expense tracking and management for any device. Send a tweet so you don't miss a bill.

Photo by Kengo via flickr.

Monitoring Tools

1. tweetbeep Keep track of conversations that mention you, your products, your company, anything, with hourly updates! You can even keep track of who's tweeting your website or blog, even if they use a shortened URL.

2. Tweet Scan Get an email when your keywords are mentioned on Twitter.

3. Convo Monitor Convo Monitor is a dashboard view that allows you to track your brand on Twitter. You also can track Twitter conversations about any topic, word, phrase, idea, or person.
4. TidyTwwet TidyTweet helps keep your Twitter feed free from inappropriate language, users and content.

During/After the Event

1. twebevent An excellent collaborative tool for your event. Live streaming and twitter chat.
2. TwitterGram Send your Flickr pix to Twitter and show people what you're up to.
3. Wiffiti It is a media application designed to show content streams online either lean back or lean forward. It creates interactive displays during events.
4. TwitCam Live streaming on twitter.
5. Tvider Share your pictures, videos and audio on twitter
6. Tweetmojo Allows you to share your videos, photos, and documents on Twitter easily.
7. twitCharts Is a simple web wizard for Google graph charts that let’s you share charts to your Twitter stream.
8. Camtweet Lets you share live video on Twitter.
9. Twitpic Let you share photos in twitter.
10. Julius Solaris at the Event Manager Blog show us "5 ways to visualize twitter at events"and how twitter entered presentations through Keynotetweet.

I guess you heard about most of these applications and used some of them already, if I am missing something you think it's relevant feel free to add it in our comments.