Does anyone know if GPS apps such as Navigon, TomTom, or any others use 3G/internet?

Specifically, Navigon.

I'm interested in purchasing it after seeing it on my brother's iphone but am afraid that it might use internet to provide information. I'm on the 200MB/month deal

So does it use just satellites/no internet or combo?

this would be on my 3Gs phone...which I'm not even sure if it comes with a GPS chip in it.