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.