Upgrading gems from 1.0.1 to 1.1.0

I followed Hivelogic tutorial to install the gems 1.0.1 on Leopard. So I had to use the following commands to upgrade:

sudo gem install rubygems-update
sudo update_rubygems

Note: sudo gem update --system did not work. It installed it in some other directory and gem env was showing version 1.0.1