Unixmen posted an Ubuntu upgrade guide
Ubuntu 11.04 Natty Narwhal Beta is released! If you have ubuntu 10.10 Maverick Meerkat or older version of ubuntu installed and you want to upgrade to the latest Ubuntu 11.04 Natty Narwhal, you can do it by following these instructions.How to upgrade from Ubuntu 10.04, 10.10 to Ubuntu 11.04 Natty Narwhal