Tweetie is a twitter client for iPhone® and iPod Touch®. It costs $2.99 from the iPhone® App Store and boasts a few features:

• Handle multiple twitter accounts.
• View your timeline, replies, direct messages and favorites.
• Browse your friends and followers.
• Post new tweets, retweet
• Reply directly to tweets and send direct messages.
• Follow and unfollow people.
• Mark tweets as favorites.
• Navigate reply chains.
• Inline web browser.
• Post links with automatic link shrinking via bit.ly.
• Upload pictures to twitpic.com.
• Update your twitter location.
• View twitter trends and perform custom searches.
• Save your favorite searches.
• Implements the full twitter API.
• Uses secure connection (https).
• New: Go to User shortcut
• New: Nearby search
• New: Themes and adjustable font size
• New: Bookmarklet support

Very cool: ability to load additional tweets from further back in your timeline (something twitteriffic won’t do). ♦♦♦♦♦