"Do phones actually have a GPS chip in them? In most cases, the answer is -no-. They uses AGPS, in which the cellular towers are used to triangulate your position from the phone's signal, rather than being derived at the phone using satellites."

This seems like a difficult question to answer on a case-by-case basis. A-GPS seems generally to be defined as using cell tower(s) to assist the GPS, not necessarily to replace it. Here's one definition, and here's another. If someone has a really, clearly documented better read on this, I'd appreciate it, but at this point if I see a cell phone advertised as "A-GPS", I don't assume either way --- i.e., it might have a stand-alone GPS, and it might not. My current assumption is that the only way to tell for sure is to dig into the detailed specs and find the specific GPS chipset (SiRF Star III or whatever). If that can't be found, I just wouldn't assume either way.