A barcode makes life easier, it has no stupid significance in relation to bible prophecy. You try remembering the price for every single different item in a supermarket etc. They save time and money, and really if you have aproblem with labour saving devices why are you on a computer? The computer is just as evil in your logic, and the computer is the other half of the "mark" - without the computer the "mark" is useless.
Fair enough, you warn about being slave of man, but really does the barcode make one a slave more than ones own ACTIONS? I think your missing the point entirely. A physical mark means nothing, but ones actions and words show who a person is.