Hi.
Debian stable (etch) has Gnome 2.14. Since it is now stable, the
only way to get a newer version of Gnome is to build from source or
wait for newer versions of Gnome on backports.org.
Debian unstable (sid) has Gnome 2.18. Orca is also now
in unstable.
I don't run Debian testing (Lenny), but I believe it is also running Gnome 2.18.
Hope this helps.
Kenny