As I noted two days ago I was unable to build Android on Ubuntu 9.10 x86-64 and thus needed to set up a virtual machine.
At first I went for my preferred virtualization solution, VirtualBox and had to notice that even though I assigned all 4 processor cores of my workstation (along with 2GiB of memory) to the virtual machine building was painfully slow. I immediately ditched the idea of using VirtualBox again and decided to give something new to me a try: the combination of kvm and qemu.
Having Intel VT-x support built into my workstation's processor I thought that this combination should give better performance, and I wasn't disappointed. To be honest, I am astonished on how fast the beast is now. Disk speed still seems to be not as fast as running things natively, but there must be a downside somewhere. :-)
After a bit of googling I also found that ubuntu-vm-builder exists, which simplifies virtual system creation tremendously.
My Android working tree is being synchronized right now, which means that I should be able to start building in a few minutes time. I hope the virtual machine stays as fast as it is right now during the build and I hope everything goes well.