Infinite Tweet, lets you write tweets longer than 140 characters using Twitlonger or Cut140 service. This tweak integrates itself into your native iOS applications i.e. Twitter, Echofon and TweetBot so you needn’t to open an external page in the browser. And not only that, but it does handle the same with photos of Instagram, so if you’re addicted to this service you can view your photos more easily from twitter applications with this modification.
You can download Infinite Tweet for $ 0.99 in Cydia, BigBoss repo.