COULOUR Lovers

 THEMELEON (www.colourlovers.com/themeleon)
Image-conscious net users can change the background designs on their Twitter accounts to suit the latest vogue.
You can try out different looks or upload a photo and this app will set it correctly for your background.

40IT (http://140it.com)

 40IT (http://140it.com)
Drag the bookmark for this site onto your toolbar in Firefox or Internet Explorer and when you post a tweet it automatically shortens the text.
It seems to work OK with Chrome too, but it is not officially supported.
It does not take a genius to reduce a post to 140 characters with common abbreviations, but I do like that it auto-shortens URLs.

tweetPhoto

tweetPhoto

TweetPhoto.com works in a similar way to Twitpic with some nice features such as stats, geotagging, adding to favourites and Facebook integration.
Pikchur.com also stands out from the crowd for its allowing users to automatically post pictures to multiple clients, including Twitter, Facebook, Friendfeed, Tumblr and Flickr.