The Current Holden Monaro based GTO production ends this summer. It was only originally meant to be sold in the USA for 3 years. Pontiac had a 3 year deal with Holden. Plus the 2006 GTO doesn't meet the new 2007 air-bag standard and would need to have that system re-engineered and then recertified which isn't worth it to sell the car for just one more year.
The Next GTO was anounced by Bob Lutz at GM last week and will be out in 2008 at about the same time as the new Camaro. Grand Prix is going RWD too around the same time.