Desktop Clients For Twitter

• TweetDeck – an Adobe AIR client (Mac/PC can manage various twitter account together)
• Tweetr (Mac/PC)
• TwitterPost (Mac OSX)
• Twhirl – another Adobe AIR client (Mac/PC)

Mobile Clients

• Fring allows to communicate with members of Skype, MSN, Messenger, Google Talk, ICQ, SIP, Twitter, Yahoo! and AIM.
• Hahlo – a web-based client
• PocketTweets (iPhone)
• Tweetsville (iPhone & iPod Touch)
• TreoTwit (Palm OS)
• Twibble (Nokia, BlackBerry, Sony Ericsson)
• Twidroid (Android mobiles)
• Twinkle (iPhone)
• TwitterBerry (BlackBerry)
• TwitterFon (iPhone & iPod Touch)
• Twitterlator (iPhone)
• TwitterMail for tweeting by email
• Twitterrific (iPhone & iPod Touch)

Clients for Multiple Accounts

• TwitterFace (coming soon!)
• Thwirl (Mac/PC) desktop client
• Tweetie (iPhone & iPod Touch)
• Matt – Multiple Account Twitter Tweeting

Firefox Add-Ons

• TweetBar – Twitter sidebar for Firefox and Flock.
• Twitterbar for tweeting from the Firefox address bar.
• TwitBin – a lightweight sidebar for tweeting.
• TwitterFox provides a tiny icon on the status bar which notifies you when your friends update their tweets. It also has a small text input field to update your tweets.
• TweetyTunes allows you to post your currently playing songs to Twitter.
• TwitterScope allows you to follow the rest of the Twitter conversation from a specified user and see all @replies to that user.

Widgets

• BeTwittered – a Google widget for Twitter. Post updates without leaving your Google home page. A full Twitter client with tabbed message views, configurable refresh rate, avatars, fonts, etc.
• Twitter Gadget – another Google widget to update your Twitter status and view your Twitter friends from your Google homepage.
• Twidget – a free Dashboard Widget for Mac OS X that allows you to update your Twitter status.
• Twitterflex – another free Dashboard Widget for Mac OS X which allows you to follow friends and update your own status.

Utilities

• Twitter Search searches Twitter conversations for keywords, hashtags, or @ replies to any user.
• Twitterfeed posts your blog RSS feed to twitter.
• Twitturly – a service for tracking what URLs people are talking about on Twitter.
• twInfluence – a service measuring the combined influence of twitterers and their followers.
• Twitter BlackList a list of known Twitter spammers.
• TwitPic for sharing your photos o Twitter.
• FriendOrFollow Who are you following that’s not following you back? Who’s following you that you’re not following back? Find out!
• Qwitter a notification service when someone stops following you.
• TwitStat – Real time Twitter Analytics
• Twitter Grader – vanity booster or crasher (depending on the grade your profile gets
• Twellow – the directory of Twitter users
• Tweetstats graphs your Twitter usage (tweets per hour, day of the week, month, whom you tweet with, your preferred Twitter client, etc.)