CoLinux for Ubuntu
To install from scratch, follow instructions for installing Debian Sid here
Now upgrade Debian Sid to Ubuntu Hoary
- Edit /etc/apt/sources.list, comment out Debian references, insert Hoary ones
- apt-get update
- apt-get dist-upgrade
Alternatively, if you already have Ubuntu installed on a separate partition, then you can follow the the instructions for running a dual-boot CoLinux setup