Twitkafly has a ton of features for Twitter on the go!
Recently in the release of the new Activator for iOS 5 (okay, maybe not to recent, but it's still a new feature as of late) you could invoke an Activator action to compose a lone tweet from anywhere on your iDevice. There was a significant lag when invoking this feature as the Twitter dialogue box hadn't opened for several seconds. iOS jailbreak Developer, Moeseth
, brought us a tweak a while back that lets you tweet from anywhere in SpringBoard without the lag of the default Activator