It used to be first come first in - free. I was usually there about midnight of the draft to get in - and got in every time.
But that was back a few years ago.
I think they are moving the draft from the Theatre in MSG to Raido city music hall.
Just a slightly larger venue.
How they set up the stage and everything elas is yet to be seen.
They used to get all the Giant and Jet fans in one area with the rest of the NFL fans anywhere that is left.
Go over to the NFL site and poke around there may be more information there.
http://www.nfl.com/draft/story/9328413