I haven't gotten the chance to check this out yet, but I just read on Lifehacker that the new beta version of Google Mobile Maps supports pseudo-GPS functionality - in addition to the ability to work with a real GPS.
Let me explain. True GPS requires a GPS receiver and can pinpoint your location with a fairly high degree of accuracy. Then there is what I call "pseudo-GPS." This is a technique that determines your rough location by using a triangulation technique. It calculates your distance from a couple of nearby cell towers and uses that to give a rough estimation of your current location. Apparently, the new Google Mobile Maps supports both techniques.
This is very cool. As I said, I haven't tried it out yet to see how it works, but I think that there is definite value in being able to see your location without having to purchase a costly GPS receiver. Sure, you probably can't use the pseudo technique to obtain detailed driving directions, but I could take or leave that feature.
Anyway, I will check this out and report back someday. If you beat me to it, let me know how you like it!