transmission 1.21 is out.

Transmission is a fast, easy, and free multi-platform BitTorrent client with a focus on being lightweight yet feature-filled.

Transmission is the new default bittorrent client for Ubuntu Hardy Heron. The version shipped with Hardy has now been superseded by a few other release.
Lately, version 1.21 has came out with some extra features.

A .deb package for Ubuntu Hardy Heron is available from debuntu repository for i386 and amd64 architectures.