In these hours the operating system (a Fedora Core variant) image which will power thoudands of One Laptop Per Child (OLPC) notebooks has been released in public.
You can download it and install inside a virtual machine from VMware, Microsoft, Parallels (also for Mac OS users), or inside QEMU. No paravirtualized image for Xen, sorry.
Some technical steps are required but it works.
Download it here and try from yourself. Or check feedbacks from current testers here.