I'm not a super tech type guy, but I did get the new Iphone 4 and for the first time in as long as I can remember, I like toting a phone with me all the time. Lots of fun things on that phone, but in regards to the trip, having the Accuterra app was a kick to have. It's a $3.00 GPS app that doesn't need cell coverage to work. Here's a link that you can check out our trip as it was recorded, including spots that we stopped and I took photos with the phone. It even kept us from getting lost at one point.
Link to the interactive map is here - you can zoom close to ground level to see the terrain we were on as well as look at pics at the location I took them. Fun!
Overview screenshot