Canonical has just released the final maintenance of Hardy Heron, that is Ubuntu 8.04.4 LTS. Although this is the final maintenance release, support on Desktops will continu till 2011 and in servers till 2013 through online updates. This release includes updated server, desktop, and alternate installation CDs for the i386 and amd64 architectures.
A total of about 70 updates have been added since Ubuntu 8.04.3 which was released in July 2009. A major update is that the installer now supports USB booting like the newer versions. The new version of Pidgin has also been backported for this release.
You can download Ubuntu 8.04.4 LTS from http://www.ubuntu.com/getubuntu/download.