Miro 3.5 has been released. The major improvement, in my opinion, is the ability to convert video and audio files for other devices — Android OS for example.
Ubuntu 10.04 is bundled with Miro 3.0. To upgrade, add the repository:
sudo add-apt-repository ppa:pcf/miro-releases
sudo apt-get update
sudo apt-get install miro
Enjoy the file conversion! :-)