Rockstar Games just released some info on GTA 5.
http://www.ign.com/articles/2012/11/08/grand-theft-auto-v-details-revealed
http://www.ign.com/articles/2012/11/08/grand-theft-auto-v-details-revealed
QuoteLos Santos will be the biggest open world in Rockstar's history, "bigger than Read Dead Redemption, Grand Theft Auto IV and San Andreas combined." Players will also be able to explore underwater areas of the city.