Rules just published for the new 600cc four strokes, Moto2, that will replace the current 250 GP bikes.
Moto2: 250cc replacement class regulations announced | The Official MotoGP Website
http://www.fim.ch/sec/documents/f_6127.pdf
Moto2: 250cc replacement class regulations announced | The Official MotoGP Website
http://www.fim.ch/sec/documents/f_6127.pdf