Lots of people who have done this keep blogs of the trip. This guy is my favorite so far. Some Korean dude decided to drive an old Mercedes Turbo Diesel on the Pan-American highway. I like his attitude and this section made me fall in love with Guatemala:
http://drivetosouthamerica.com/photo-journal/guatemala/
I have been to Colombia and the girls there are just flat out insane. Imagine a girl like this working as a shipping clerk in the US.