Add another free iPhone Twitter app to test out. Here's...

TweetDeck 1.0 (iTunes App Store)

It is surprisingly similar to TweetDeck's desktop AIR app design showing several columns to choose from when it starts up. Tapping on any of the columns (swipe horizontally to see each column) zooms it to full screen for use. It is supposed to let you sync columns with TweetDeck installed on other platforms (desktop/notebook). However, after creating an account on the desktop, TweetDeck would not accept my email address as a valid login name.

TweetDeck for iPhone supports multiple accounts. And ,it has an option to refersh by shaking your iPhone or iPod touch. It seems simpler to just tap the Refesh button on the bottom of the screen though. My initial impression is that TweetDeck for iPhone requires more screen taps than TwitterFon or Twitterrific does for simple tasks like checking mentions or direct messages.

The AIR based TweetDeck hasn't grown on me yet (still using Twhirl). But, I'll give the iPhone version a try for a couple of days before deciding whether or not it is a keeper.