What Android distro can boot from USB stick in PC/Laptop? I have an old HP Pavilion dv2000 laptop with a busted hard drive. I want to put a compatible Android distro onto a USB thumb, plug this in to the laptop and boot into it and use it for casual www browsing. 

Firstly, is this possible and if so, is LiveAndroid my only option?
http://www.android-x86.org/

This is the only android distribution for Intel/AMD processors that I am aware of. It has little support, but is actively maintained. The latest version is a release candidate for Android 2.3. Obviously hardware support is hit and miss. For what it's worth it runs very well on my EEE PC.

You can install the ISO to a USB drive with Unetbootin, or use a drive imaging tool with the .img file.