How to run Linux inside of Windows with Virtualbox

I've run Linux inside of Windows before, but there were a few problems that I hadn't worked out. I finally got it working tonight though. (screenshot attached of Ubuntu 9.04 running inside of Windows XP)

To run Linux inside of Windows XP, there are instructions here.

The missing key for me was to "install guest additions" in virtualbox, which let me expand Ubuntu's screen resolution to a usable size.

Thanks to @ironhelixx and @joshmccormack for pointing me in the right direction.

I'm using Windows XP because I need speech to text software that doesn't run on Linux -- but it's difficult to get work done in Windows XP. So by running Ubuntu inside of Windows XP I can control Linux with voice commands (Dragon NaturallySpeaking).