Run the following commands in your terminal:
On Ubuntu 11.04:
add-apt-repository ppa:gnome3-team/gnome3 aptitude update aptitude dist-upgrade aptitude install gnome-shell
On Ubuntu 10.10:
add-apt-repository ppa:ubuntu-desktop/gnome3-builds aptitude update aptitude install gnome3-session
Note: This repository is outdated !
Lock out and back in, after completing the installation. (Choose Gnome3)
Remove:
aptitude install ppa-purge ppa-purge ppa:gnome3-team/gnome3
Links: