For ubuntu 8.10 go here
Ubuntu restricted extras offline installer is a combination of packages containing multimedia codec and other most widely used restricted packages. This must be one of the most wanted package any body like to install after installing fresh Ubuntu. Installing ubuntu restricted extras will enable multimedia codec, java run time, flash, unrar, commanly used M$ fonts and libdvdcss (required to play encrepted DVDs). If you do not have internet connection then this package is for you. Download Ubuntu_restricted_extras_offline_installer_ubuntu_9.10.tar from this link http://rapidshare.com/files/305466863/Ubuntu_restricted_extras_offline_installer_ubuntu_9.10.tar.gz and save it in the desktop or home folder. Then right click on it and select extract here option. Now you can see new folder. Go to extracted (new) folder and double click on install.sh file. This will bring up new (small) window in which select run in terminal option. Now you are done. You can check it by playing some video and audio files.