A couple of people have recompiled the OS so it's capable of running on a common x86 platform. This is just in time to see what Android is really like, before Acer, Asus, MSI and others officially release their netbooks with the operating system preloaded on them.
The PC version has been ported from an Asustek EeePC 701 netbook running Android. As with every other try-before-you-buy LiveCD, you simply download the ISO file, burn it onto a CD or DVD, and then boot with the disc.
With a LiveCD, there's no need to install the OS, so you can test-drive the software without writing it to your system's hard disk. The LiveCD can also run under virtualisation such as VirtualBox or VMware or the other thing by the Vole.
You can grab the Liveandroid version 0.2 from Google.