What Android distro can boot from USB stick in PC/Laptop?
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.