Comment 2 for bug 574067

Thanks for your report. This is not a bug but a design decision. NetworkManager is now the default in Lucid, and network-admin doesn't play well with it. NetworkManager provides everything you may find in network-admin, but less buggy, so please use that tool.

The connections tab has been removed to avoid misleading users, since configuring interfaces there would conflict with NetworkManager, and break your network in unexpected ways.

network-admin is indeed part of the gnome-network-admin binary package, not gnome-system-tools.