Here's the one-liner version of the Feisty (7.04) to Gutsy (7.10) upgrade (in case the distribution upgrade tool fails -- it failed in my computer=. Copy and paste this on an open console window, and you're very probably set:
sudo sed -i 's/feisty/gutsy/g' /etc/apt/sources.list && sudo apt-get update && sudo apt-get dist-upgrade
Substitute feisty for the distribution name you're using and gutsy for the distribution name you want to upgrade to.
If at some point any of those processes fail, you will be returned back to the console.
dist-upgrade will require your confirmation, so don't just take off before the confirmation question.