Echofon (formerly ‘Twitterfon’) is an easy to use, super-fast Twitter app for the iPhone and iPod Touch.
It’s easy to do common Twitter tasks such as viewing your timeline, messages, replies, lists and favorites. Echofon has a powerful tweet-authoring where you can write tweets, take photos, record video (3GS only) and update your current location.
Keep up with what’s happening on Twitter with Echofon’s search tools. You can search Twitter, view trending topics (with explanations), nearby tweets and find users easily from the search tab.