To install TweetDeck on Ubuntu, follow the below steps:

1. Go here and download the latest package of Adobe Air for Linux:

   http://get.adobe.com/air/

2. Open a Terminal and browse to where you downloaded the installer file (at the time of this post it was called “AdobeAIRInstaller.bin”)
3. Type chmod +x AdobeAIRInstaller.bin and press Enter
4. Type sudo ./AdobeAIRInstaller.bin and press Enter
5. Enter your password and this will launch the installer. Follow the prompts accordingly.
6. Now go here and download the TweetDeck Air file:

   http://www.tweetdeck.com/beta/

7. Open with Adobe Air and install the application by following the prompts.  You will need your Admin password.

This is taken from PCSympathy.com. The Original Link is here.