I have recently jumped back into Twitter – reignited my account, followed our Prime Minister and Leader of the Opposition (and promptly received a Twitter back that they were following me…now I feel important!), tried to find many of my colleagues on Twitter without success – but persevering!
The big positive difference has been installing a Twitter application on my iPhone – now I can create Tweets on the go, and also browse incoming Tweets when I am mobile – I feel this really unlocks the value.
Comments from Twitter users?
The Strategy Group 
have you tried http://www.twitxr.com
it allows you to attach photos with your tweet and has some other cool features.