qemu is great for doing some quick-and-dirty stuff.
sudo qemu -hda /dev/sdc -cdrom ubuntu-10.04-server-i386.iso -m 128 -net nic,vlan=0 -net user,vlan=0
qemu -hda flashimg.i386-20101001 -m 128 -net nic,vlan=0 -net user,vlan=0