I just installed Gwibber today. Let me tell you, it’s better than twhirl (no Adobe Air needed!), it runs on Linux, and it feeds Twitter, Pownce, Identi.ca, digg, Facebook, Jaiku, and Flickr.
It’s pretty fast and stable. It won’t be taking over Flock anytime soon, but it’s pretty much a killer app when it comes to microblogging.
Now, I’m mostly using Identi.ca for all of my microblogging needs, but I still follow my peeps on twitter and also on Pownce. Identi.ca is really the next big thing on the internet, I think. I think it has the ability to “take over” what twitter is doing very easily, especially since anyone can set up a server using the laconica software.
Gwibber isn’t available for Windows (yet) but one of the devs said that they would probably be porting it over there pretty soon. I’d be able to quit using Digsby in favor of this, since I don’t have to repost using it (I just set it up to post to all my accounts).
Give it a shot using these instructions. It’s really pretty easy to install (follow the instructions) if you’re running Ubuntu.