Tweetsville bills itself as a “humble” twitter client for the iPhone®. It boasts many useful features:

• Shows up to 200 tweets:
  Rich text display; bold will display as bold, etc.;
  Clickable inline links and @names;
• Two looks: Balloon and Simple
• Displays border for tweets in which you are referenced in Balloon mode.
• Tap a tweet to view details, send replies, and mark as a favorite.
• Explore the latest hot topics with Trends.
• Search the Twitterverse:
  Search using official Twitter advanced query terms;
  Location/Date-based search supported;
• Send and receive direct messages:
  Distinctive look, to separate it from tweets;
  Threaded display of sent/received messages;
• View details of tweets:
  Reply to user (ties directly to this message in the web site – more accurate than a simple @reply);
  Send direct message to user;
  Mark tweets as favorites;
  Delete your own tweets;
  View a user’s profile;
• View user profile information:
  View favorites/history;
  View a user’s friends/followers;
• Compose tweets and direct messages with ease:
  Upload images via TwitPic;
  Type-ahead name matching of friends when sending direct messages.

Tweetsville is available at the App Store for $3.99 and requires the iPhone® 2.0 software update. ♦♦♦♦