Can HDD clones be bootable?

I was wondering if it is at all possible to clone a hard drive and make it bootable as well. I would like to clone my hard drive onto a USB HDD and take the USB drive with me when I travel. My ultimate goal would be to be able to change the BIOS of other machines allowing me to boot directly from the USB drive.

Has anyone one done this before? Can it be done? Or would something like PC Anywhere be a better idea. I have never used PC Anywhere, but I hear you can connect to your computer from a remote location and work with your files.

Thanks for your help again TechRepublic members!