Can't remember the title of this book?

Its about a little boy who lives in a sort of brave new worldish place. And he is chosen I guess a being different from the other children. Every one grows up and their jobs are picked for them, some girls will become the people who give birth and the smarter kids get better jobs. Anyways so this boys job is to recieve memories of how the world used to be. And it causes him physical and mental pain, the memories are given to him by a really old man. Thats all I remember really except at the end the boy and someone else (another child who might be chosen for his job I think) are outside of their normal "world" and they sled down a snow covered hill. Any help on what book this is would be much appreciated!