As I stated earlier, GPS units are generally frowned upon. Especially when you take someone on your favorite single track stash and the A hole tracks it and posts it all over the internet!
I do have to admit that I like the iPhone as a GPS. I have friends who wrote the GPSkit and GISkit apps which work well. Many people don't realize that it works off satellite signals rather than cell towers. This is great for bringing it abroad. I just lock the sim card and use the satellites and also wifi when available.
You can download all the maps you want for free. I downloaded aerial views of all the larger towns and cities.
I also downloaded Google Terrain versions of the entire area we're going to travel around.
I guess I look at the iPhone as the minimalists version of a GPS. You just don't want to use or rely on it too much because you'll lose your natural route finding technique.
We leave in the morning.