We've now pushed many pieces of the GNOME 3.8 Beta (3.7.90) to the GNOME 3 PPA.

If you have already been using the Staging PPA, be sure you alsohave the GNOME3 PPA enabled for raring as we will be removing the duplicate packages there soon. The Staging PPA is for the pieces of GNOME 3.7/3.8 that still need work or have known regressions. For a longer explanation, see my email to the ubuntu-gnome list.