I "reextended" my extended GMPP warranty last week through Black Ponitac Cadillac (gmoutlet). Allen was great to deal with!
FYI - It was $2700 for 3 years, 45k miles, $200 Deductible.
That takes me up to 101K miles or May of 2009!
If I hadn't had sizable claims in the past, I would have saved my money. All it takes is a tranny failure or another blown axle/differential and the warranty pays for itself.