[ Thanks to Deepak for this link.
]
“The Gnome 3 PPA has been available only for Natty
users. But now, Ubuntu Desktop team have have set up a PPA to give
Maverick users some upstream testing elements of the desktop.“There many issues in upgrading to Gnome 3, the very fact is
that Gnome 3 hasn’t been released. This upgrade cannot be easily
revered, so be aware of what it does.”