1. wget http://rubyforge.org/frs/download.php/69365/rubygems-1.3.6.tgz
2. Extract : tar xvzf rubygems-1.3.6.tgz
3. cd to rubygems directory and run : ruby setup.rb
4. sudo ln -s /usr/bin/gem1.8 /usr/bin/gem
Check version by either : gem -v or gem env
