yes...you need to have a bios that will allow bios boot order set to usb b4 hard drives etc
put a distro on the usb stick.
2) some companies sell sticks with pre-installed distro like mandriva or most of the live cds like puppy and dsl have an option to make a usb
3) somewhat harder is to make your own....which invariably needs to have certain kernel qualities such as squashfs....cramfs or some other ram set up.
I suggest you first try a live cd system to usb