Debian Planet has removed their GNOME 2.2 mirror for Debian GNU/Linux 3.0 because of excessive bandwidth.

An alternative mirror is available at: http://ftp.acc.umu.se/mirror/mirrors.evilgeniuses.org.uk/debian/backports/woody/gnome2.2/

Add this to your /etc/apt/sources.list:
deb http://ftp.acc.umu.se/mirror/mirrors.evilgeniuses.org.uk/debian/backports/woody gnome2.2/
deb-src http://ftp.acc.umu.se/mirror/mirrors.evilgeniuses.org.uk/debian/backports/woody gnome2.2/

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Installation instructions