Conceptually (setting aside the simple math explanation) 0 means nothing, so even if you have infinite number of nothing, you still have nothing. Likewise, if you have zero infinities, you still have nothing.
I think the question is not so clear if we have \lim_{b \goes \infty} 0.b = 0 now it should be different if we ask \lim_{b \goes \infty, c \goes 0} c.b = indeterminate, I should also say that infinite is not a number
I realize that Miguel, but actually i was asking myself about be the sense in to make such question, because as i know $\hat{R}$ (real with infty) just have the order properties and the nested intervals property, and with that property it is possible to prove that \infty*0 should not be a number different of zero, now should be reasonable to assume that infty * 0 is zero and also that \infty.0 = indeterminate, but this I think it is part of the some necessary definitions about infty as number