It is very easy to check your timeline on Identica with TweetDeck.
To add an Identi.ca account, go to the settings (spanner icon in the top right corner) and Accounts. Click on the Add New Account button. The bottom half of the window will show all the types of accounts that can be added to TweetDeck. Select Twitter and enter the Identi.ca username and password in the “Twitter” username and password field. Click on the Advanced Options link below the password field to reveal more options. In the Twitter Base URL text box, enter http://identi.ca/index.php/api/
and check the details by clicking on the Verify Details button. This will either add or show an error if the details are incorrect. Lastly, save the settings.
How To Use TweetDeck With Identi.ca [w/ Adobe Air Ubuntu Installation Instructions]