Whats the name of that book thats becoming a movie about a teenage kids who travels/backpacks and ends up?

in ALASKA ?

Are you thinking of "Into the Wild" by Jon Krakauer, about the young man who hitchhiked to Alaska and was later found dead inside an abandoned bus?

http://www.amazon.com/Into-Wild-Jon-Krakauer/dp/0385486804/?tag=24680e-20

http://www.imdb.com/title/tt0758758/