TwitterGram, a free online tool that can auto tweet about your uploaded photo.TwitterGram checks your flickr feed about every 10 minutes and only the most recent post within the hour is sent to Twitter.

GeoChirp is a mashup of Google Maps and Twitter, The Google Maps lets you easily choose the location from where you want to see the tweets from, or search for people Twittering for specific things in a specific area or you can also see the recent tweets from people from your location, You can set the number of tweets that you want to see and a search radius (miles) within which you want to see tweets from.

Quitter, which is a text-based twitter client with which you can read, post, reply and retweet from the DOS prompt of Windows and is portable and stores settings in an XML file and also shorten URL’s using TinyURL from DOS.

Create a ebook called Tweetbook with all your tweets, replies and twitter favorites using TweetBook.A tweetbook can have a maximum of 3200 tweets.

Add overlay images to your Twitter profile images using avartize, and change you twitter profile image from avartize.

Remidr is an online reminder service that can remind your activities through Twitter, EMail, IM via GTalk/Jabber and SMS.

TweetCaster is a free blackberry twitter client with multi-account toggle support, URL shortening via TinyURL, picture sharing and many more from Blackberry Phone

Create your own Twitter background Theme with customizations like color,text,images,and objects in various resolutions that can also be automatically updated in your twitter background.