Organizers for the Rock Vegas festival, presented by Rockstar Energy Drink, revealed on Monday that the event will be headlined by Godsmack, Marilyn Manson, Shinedown and Rob Zombie.  The two-day event is scheduled for September 28th and 29th, with tickets going on-sale this Saturday.  Other acts confirmed for the festival include STaind, Papa Roach, Adelita's Way, Stone Sour, and many more.  For more information, go to RockVegasFest.com.