Support for regular Ubuntu releases ceases 18 months after release, for LTS versions support ceases after 3 years. Ubuntu 8.10 was of the former variety. The repositories for old versions exist at a different location, if anyone needs this in the future the repository(old-releases) for Intrepid Ibex is:
deb http://old-releases.ubuntu.com/ubuntu/ intrepid main restricted
you'll have to add the above line to your /etc/apt/sources.list file
sudo gedit /etc/apt/sources.list
should open up /etc/apt/sources.list for editing. While you are at it you might want to remove the old entries.
For other versions just replace intrepid in the sources.list apt line with the name of your version of ubuntu.
Old Ubuntu Releases Website: http://old-releases.ubuntu.com/releases/
More information on configuring your apt sources for Old Releases : http://soniahamilton.wordpress.com/2...ons-of-ubuntu/
It would save people a lot of trouble if the folks at Ubuntu could send this information via an update before they withdrawing support for older versions...