One of the most popular Twitter clients for the iPhone is Tweetie. Winner of an Apple Design Award, the iPhone app (and the Mac OS X app) has defined the Twitter experience for many users.

Today, Tweetie’s developer, Loren Brichter announced Tweetie 2.0, coming soon for the iPhone and Mac OS X. The final Tweetie 2.0 iPhone beta was seeded to users this morning and if all goes well, the final version will be submitted to Apple later this week.

I’ve had the opportunity to play and use Tweetie 2.0 for several weeks, and below, we’re able to show you some screenshots of the new Tweetie and its features.

Complete Rewrite

Tweetie 2.0 is a complete rewrite of the original iPhone app and it combines the codebases of Tweetie for Mac and Tweetie for iPhone. This means that the applications will not only have more in common, but that changes will be easier to push out to both apps.

Tweetie 2.0 has a ton of new stuff – including support for the new Project Retweet that we previewed last week. The upcoming Twitter geolocation features will also be integrated as soon as those APIs become public.

Additionally, you have the ability to have your saved searches in Tweetie sync with Twitter, view threaded conversations, and link up your Twitter contacts with your iPhone Address Book – which is a great way to keep your contacts aligned (or to quickly call someone right from viewing their Twitter profile.)

New Features

Other features include:

Preview short URLs

Block/follow from multiple accounts
Receive device notifications from select users
Full landscape support (fully configurable)
Improved gesture support
Drafts management
A multiple attachment manager, hashtag picker and more
When you start the app you go right back to where you last were when you quit and caching makes it fast and easy to keep up with new and older tweets.

Still Simple and Sexy

The entire application is really a joy to use. What made the original Tweetie so great is still there, along with all kinds of features that leverage not only the new Twitter APIs and third-party services, but the new iPhone OS 3.0 features too.

Tweetie 2.0 is a whole new app, and it will require the iPhone 3.0 OS and will cost $2.99 in the App Store, the same price as the original Tweetie.

For Mac OS X users, Tweetie 2 will be a free upgrade for all existing users.

What do you think about the new look and features of Tweetie 2.0? What is your favorite iPhone Twitter client?