No, they are just ads. Unless it is some kind of promotion on an official product (which, because the Xbox360 isn't even out yet, there won't be any for some time), those ads will just lead you to a site that will give your computer a virus.
some ads do like freexbox360.com but, you have to buy something else. and every ten minutes half the people their drank about $300 worth of mountain dew which is what a $100 less whoop dee doo $100 off but, 25 pounds heavier.