(via www.ubuntugeek.com)
This tutorial will explain how to Upgrade Ubuntu 8.04 (Hardy Heron) to Ubuntu 8.10 (Intrepid Ibix) released on the 30th of October 2008.By default Ubuntu 8.04 LTS will not offer a upgrade to 8.10. This is because the 8.04 LTS version is a long term support release and 8.10 is a regular release. Upgrades from 8.04 LTS to 8.10 are fully supported, of course, and easy to enable.