Here are a few of my favorite twitter applications, tools and plugins.  Twitter applications can be called by different names. They are sometimes called as “twitter tools”, “twitter add-ons” and the likes. But whatever the name they are called, they are simply websites which have built-in scripts that complement Twitter.

Apps, Widgets and Plugins – Windows

Triqqr – Submit tweets directly to Twitter and view user profiles.

Pwytter – Cross platform Python Twitter client with Asian character support.

Teletwitter – Experimental open source client.

TwitBox – View and submit tweets, see replies and direct messages, delete your own tweets, and multiple account support.

Twitterlicious – Update Twitter status, easily check replies and direct messages.

Twitteroo – Client with rurl URL shortening, clickable links and tweets, customization, and both public and friend timelines.

Chirrup – Twitter client with extensive Japanese language support.

TwittIt – Extremely compact and simple app for submitting tweets.

MadTwitter – A reincarnation of Twitterrific, except on Windows.

Twitter CLI – Post tweets via the command line.

What’s Up? – Gadget that allows you to see latest tweets from your friends.

Twadget – Simple gadget that lets you view and submit tweets right from Vista’s Sidebar.

KipFolio Widget – Simple Twitter widget for KipFolio.

Twitter-Sync for Yahoo – Syncs Twitter status with Yahoo Messenger status.

TwitterYM – Simple Yahoo Messenger status updater.

Twessenger – Updates Live Messenger status to reflect latest tweet.

Twit4Live – Set status message as latest tweet, send tweets from within Live Messenger, and send tweets to contacts.

Apps, Widgets and Plugins – Mac

Twitterrific – A compact client that publishes tweets, shows unread tweets, has easy access to profile pages, shows either public or friend timeline, and more.

TwitterPost – Basic client that submits tweets, shows your current iTunes track in your feed, and more.

Twitgit – Read your friend’s tweets and submit your own, right in Dashboard.

TweetAhead – Schedule tweets to be posted ahead of time with a simple Dashboard widget.

Twitterlex – Dashboard widget that shows your friend’s latest tweets as well as allows you to submit tweets.

Twidget – Update your Twitter status within Dashboard.

TikiTwit – Match your iChat status to your last tweet.

Apps, Widgets and Plugins – Linux

BLT – Perl script that lets you see what your friends are doing right from the Terminal.

Twitter for Vim – Publish tweets right within Vim.

ZenTwitter – A GUI frontend for Twitter using zenity and curl.

Twitux – Twitter client for the GNOME desktop.

gTwitter – GTK+ based app inspired by Twitterrific.

Twitter.el – Publish tweets while in Emacs.

Twitbar – Post tweets from the GNOME deskbar.

Twit.el – Another utility that allows publishing of tweets within Emacs.

Cross-platform Apps, Widgets and Plugins

Tweetr – Submit tweets, upload files, urltea built in, delete messages.

Spaz – Cross-platform client built with AIR.

Tweeter – Java based client with customizable UI.

Twinja – AIR based client which allows you to follow users on the fly.

Search

Twitterverse – Search through archived public timelines and tweets.

Twittersearch – Search Twitter and tweets by word.

Terraminds – Search for specific users or tweets.

TwitDir – Allows user to search for users by name, location, or username.

Browser Plugins

TwitBin – Send and view tweets right within Firefox.

TwittyTunes – A FoxyTunes addon that posts what you’re currently listening to Twitter.

Shareaholic – Share links and webpages via Twitter right within Firefox.

Search Plugin – Tweet right from the Firefox search box.

Tweetbar – Put Twitter on your Firefox sidebar.

Twippera – Twitter widget for Opera that can send and view tweets.

TwitterFox – Compact Firefox extension that can publish and view tweets.

Mobile

iTweet – A mobile Twitter site designed for the iPhone.

iTwit – Mobile version of Twitter made for the iPhone.

Tweeter – Twitter on your mobile phone while avoiding text message charges.

Jargong – Browse Flickr, do some social networking, but most importantly, check and publish tweets.

WildSets – Extensve Twitter app for mobile phones.

TwitterBerry – Twitter built for various BlackBerry devices. Update and view timelines with ease.

jTwitter – View timelines, enter updates, and more, all on your mobile phone.

TreoTwit – Easily check and update your Twitter right from your Treo.

Random/Other

Twittervision – See where in the world people are submitting tweets from, real time.

TwitThis – Allow visitors to your site to easily share a page or post via Twitter.

MoniTwitter – Receive important updates about your site via Twitter.

TwitterNotes – Share private or public notes via Twitter.

RSS2Twitter – Share any RSS feed on Twitter, and have new RSS items automatically be tweeted.

TwitterBuzz – Find out what is being most linked to on Twitter.

Twitterholic – Shows the top users and accounts on Twitter.