At the end of the regular season, the next season's draft class will appear. The "draftboard" or war room page will show at the start of the new season.
In a perfect world, I'd like to know maybe even a season earlier, to better emulate what goes on in real life. Obviously with changes going on during the season, but being able to make an informed decision on whether to trade for a QB, draft a QB or draft a QB next year, that's sort of vital. :-)
This has been brought up before and if I remember right, JDB said that the reason the draft class doesn't come out sooner is because, if the draft is strong, teams would tank to get the first draft pick.