You can use the following steps to easily upgrade Ubuntu Linux server (or workstation) 8.x to 9.10 (latest version as of this posting), either locally or remotely over ssh from a terminal command line.
First, apply latest updates to Ubuntu 8.x using:
sudo apt-get update
sudo apt-get upgrade
Next, install update-manager-core (if it is not already installed):
sudo apt-get install update-manager-core
Finally, start the upgrade:
And just follow the on-screen instructions to complete the Ubuntu 9.10 upgrade.