I have gotten it to work and it does work well. I am only on EDGE as well.
When I signed up, I selected "both" referring to phone and wireless. That caused the "GPS" to be close, but off by a few blocks. Which is funny, as I can't connect to any wireless points on my iPhone. I went back into the Navazon website and changed from "both" to "phone" (where it says "Is your Pocket PC equipped with
. That made it very accurate.
I signed up on the website and logged in on my iPhone. Looks really good.
There is something on the website about rewards, where they allow you to earn money, but it is far from explained. Edit: I was on my.navizon.com, everything is explained on navizon.com.