I read about release new GNOME 3.4. How to update from GNOME 3.2 (upgrade manager does not tell me about the new Update when check).
Gnome 3.4 will be available in the default Ubuntu repositories for the 12.10 release. Ubuntu 12.04 LTS uses many 3.4 components, but to install it in full, add the GNOME3 team's PPA to your Software Sources.
Keep in mind that Gnome is a major component of your user experience, and — in this PPA — is being maintained by a third party, not Canonical. Instability may occur.
Ubuntu From Ubuntu 11.10 onwards, GNOME 3 is just a click away.