This was created by Allen Lowe (+ his cute little kid) and Dan Rabbit who's behind the meet-box music player design. As said this is already a part of their Elementary OS which was released few months ago but since Elementary was actually a Launchpad project, you can use it in Ubuntu as well.
It's still at its early stage so few features such as Google Sync, Postler integration and D-bus support, etc are on their way.
*. Add/Edit and view your contacts - Insert first/middle names, organization, e-mail addresses, birthday, pictures, etc.
*. Search easily within the app.
*. Import and Exporting.
*. Some contact info could become link (Google map integration with an address for instance).
|It's so good that, Lord Vader hates it ... :P|
So if you want to install Dexter in Ubuntu 11.04/10.10 or 10.04, then open your Terminal as usual and use the below command.
sudo add-apt-repository ppa:elementaryart/elementary-dev
sudo apt-get update
sudo apt-get install dexter