Ubuntu 8.10, “Intrepid Ibex” launched today. It’s ready for download, and if you are already using an earlier revision of Ubuntu, it’s in the software repositories for upgrade. If you need a tutorial for this process, I recommend Christer Edwards’ site, Ubuntu Tutorials
Since 8.04 is a Long Term Support edition, be sure to go to System->Administration->Software Sources and choose to show “Normal Releases” under the Updates tab.
If you do the upgrade over the wire, consider downloading the Bittorrent image of the CD anyway. Not only is it terribly useful to have a physical copy of the CD in case of emergencies, it will make downloads that much faster for anyone coming to Ubuntu new.