aptでインストールできるバージョン一覧がみたい

apt-cache policy hogehoge
でできる。

# apt-cache policy mongodb-org
mongodb-org:
  Installed: (none)
  Candidate: 2.6.6
  Version table:
     2.6.6 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.5 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.4 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.3 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.2 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.1 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.0 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.0~rc3 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.0~rc2 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.0~rc1 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages
     2.6.0~rc0 0
        500 http://downloads-distro.mongodb.org/repo/ubuntu-upstart/ dist/10gen amd64 Packages