Make him a cookbook filled with easy college kid recipes! You could either just use a notebook and write down the recipes, or use a website to help create it for you. Here's one: http://funadvice.com/r/btsj2q5nt4b. Another idea is to make him a bracelet out of strips of leather or something. That might be cool. Or you could just make him a sweet card, and throw in a picture of you guys in it!
I like Niky's idea or maybe you can make a quilt or crochet an afgan for him to take with that he can cover himself up with and think of home. You can actually get an afgan made with pictures on it too. Your mom/dad might be able to help with the cost. if you can't afford it as well as, get in on the act of pic selection.
You could get him a picture of his role model,cld be an artist,author,athletes or whoever u think he loves best.it would always bring a smile to his face wen he sees d picture in his room....
Maybe a framed picture collage, full of memories/good times he could hang in his room.....every time he comes in, he'll think of home :-)
make him a home video so if he starts to miss the family he can watch it and hear all of your voices and see you :)