Qemu is an Emulation tool for Linux and supports multiple processors and operating systems.
It's homepage on the web is at http://fabrice.bellard.free.fr/qemu/
A useful page for installing other operating systems on qemu is http://www.debian-administration.org/articles/40
See also: QemuNotes
Here is how IanMcDonald is getting qemu running Linux.
Create a disk image like:
qemu-img create file1.img 5G
which creates an image of 5 Gigabyte.
Start qemu as follows:
qemu -boot d -cdrom /dev/cdrom -hda hd.img
Install the operating system. And then start qemu as below:
qemu -hda hd.img -boot c
However this created problems getting files in and out so better to create a loopback file system. For more on this see UserModeLinux.
2 pages link to Qemu: