Most cell phones have assisted GPS, in that they need to be able to talk to a base station to do a complete location calculation. That may not be true in some later phones...

Can the 3GS do GPS location when you are out of range of cell towers? That would be the big question.

As far as the iPad, I have not seen a list of features that has GPS included. I have seen feature lists that discuss AGPS, which is assisted, and not true (as in chart plotter or handheld) GPS.