As anyone trying to download or upgrade the latest version of Ubuntu likely found, the servers at Ubuntu can get pretty overwhelmed, especially on new release days. The (unofficial) Ubuntu Blog points out a list of mirror sites you can use to speed up your software updates and avoid strained servers. Look through the "Mirror-Mirrors" list for a location near you, copy the "http://" or "ftp://" line, and then head to your system's sources list, found in /etc/apt/sources.list. Make a backup copy, and then replace all instances of
http://us.archive.ubuntu.com/ubuntu with your mirror server line, and you should notice faster response times when updating or downloading new packages.