At the end of your season in your NCAA Dynasty, there's a list of all players leaving for the NFL. I believe after you're done looking at at the players and try to exit, there's an option to export the draft class. Do that and it's saved to your memory card. I haven't gotten Madden this year (probably won't at all), but I remember in previous versions, when you get to the offseason, there is always an option to import the draft class.