Take time to map them out on other programs, as the GPS maps are often outdated. You will miss a lot of appointments if you trust them completely.

I'm not sure how this would help in any way? How is the GPS going to help you sell a house - or help buyers buy a house? 

Bo this GPS system could be downloaded on a buyer's cellphone giving them immediate info about any home they choose or one they happen to drive by. How many beds, baths, square footage, and how much it sold for last, etc. If I use it on my website and make it available to anyone who wants it, I could brand the GPS with my Realtors contact info and the IDX pushed to their cellphone enabling buyers to call me with their questions and hopefully to use as their buyers agent. IDX on websites right now is branded much the same way with my realtor contact info for buyers to call me about properties to act as their buyers agent.

It look like GPS is out there and could be a major advantage to some agents in some markets. But here on the Cape, I spoke with a very knowledgeable broker who uses GPS who says that realtors on the Cape, the majority being female could care less and dont want to be bothered wth hot and upcoming technologies. They prefer to sell real estate the old fashioned way even with gas going to $4 per gallon!