Jeep.com is showing 0% for 36, 48, 60, and 72 months as an incentive for 2008 model Wranglers in the southeast and not showing for 2009's.
Two thoughts here: First, if you have to finance a vehicle for six years to make it affordable then you're buying too much vehicle. You're upside down for too long; it limits your options too much. Not a wise choice.
Second, any leftover 2008's become two year old Jeep's when the first 2010 model hits the lot. Resale and insurance payout values only consider the model year; they don't care when you bought it, they just care what the blue book says. Make sure you factor that loss of value into what you pay. I wouldn't touch a 2008 unless I was getting it for at least $2500-3000 less than the equivalent 2009. (that's in terms of negotiated prices not sticker)
'09 Unlimited Rubicon with a few gewgaws and doodads