A free English-Russian dictionary: Mueller 7 GPL. It can be installed by downloading it and running 


mkdir -p ~/.stardict/dic && tar xjvf mueller7.tar.bz2 -C ~/.stardict/dic

It is possible to download other popular dictionaries using these links:

  1. StarDict dictionaries in Debian project
  2. StarDict dictionaries in Fedora project
  3. StarDict dictionaries in Arch Linux user repository
  4. XDXF project repository