Turpial is a native Linux Twitter - and now Identi.ca too - client.
The latest Turpial from GIT (currently version 1.4 alpha 1) finally adds Identi.ca support - but unfortunately you won't be able to login to both Twitter and Identi.ca in the same time.
There are some other interesting features in Turpial 1.4 alpha 1 such as Twitter Lists support, a refresh button for Replies, Timeline and Direct Messages and also, the notification area now lets you know when you have new tweets:
The latest Turpial 1.4 alpha 1 is available in our unstable PPA (the version in the PPA is named 1.3.3+git20100802 but that's actually 1.4 alpha 1) so you can install it in Ubuntu Karmic, Lucid and Maverick using the following commands:
sudo add-apt-repository ppa:webupd8team/unstable
sudo apt-get update
sudo apt-get install turpial
Remember, this is an alpha version so expect to find some bugs!
Thanks to Ubuntizando El Planeta for the news!