Deluge: A cross platform bittorrent client

Deluge is a full-featured BitTorrent client for Linux, OS X, Unix and Windows. It has been designed using the client server model with a daemon process that handles all the bittorrent activity. The Deluge daemon is able to run on headless machines with the user-interfaces being able to connect remotely from any platform. Deluge features a rich plugin collection; in fact, most of Deluge's functionality is available in the form of plugins.
Installation on Ubuntu
As already mentioned , Deluge is available on a wide variety of platforms. For Ubuntu,Deluge is available in the universe repository. Cutting edge versions of Deluge is also available as a PPA via launchpad.
For installation from PPA, add the following lines to /etc/apt/sources.list
deb http://ppa.launchpad.net/deluge-team/ppa/ubuntu jaunty main
Import the key from the PPA site.
https://launchpad.net/~deluge-team/+archive/ppa
Install deluge
$ sudo apt-get install deluge

Screen shots.