Virus scanning with Ubuntu live CD and clamAV

Boot up an Ubuntu Live CD (in this case hardy) and run:
sudo passwd root # enter new root password twice
su # enter root password
echo "deb $dist main" >> /etc/apt/sources.list
echo "deb-src $dist main" >> /etc/apt/sources.list
apt-get -y update; apt-get -y --force-yes install clamav
# open the desired media from the Places menu to mount it
df #to see what it is mounted as (probably /media/disk)
cd /media
clamscan -r -l /var/log/clam
grep FOUND /var/log/clam

Some useful tips are here:
Note that in intrepid, it is necessary to enable the "universe" repository first, and reload.