There had been numerous reports and speculations in the past couple of months on where the 2nd season would be filmed. The Jersey Shore was not an option because MTV wanted to start filming this month, and needed a warmer climate.
According to the Miami Herald, some locals did protest MTV bringing the show to their home town, but despite their cries, it is said to be a done deal. The 2nd season of Kourtney and Khloe Take Miami is also currently filming in Miami. Perhaps we will have some reality cross contamination with the two shows.
The new season is scheduled to begin filming in 2 weeks.