I heard they were starting '06 production in early July. Edmunds.com shows the '06 model already with a $1,000 dealer incentive, but I'm not sure if this is correct.
http://www.edmunds.com/new/2006/hummer/h2/100541823/incentives.html?vdp=off&setzip=37363&state=TN&tid= edmunds.n.incentivesmip.incentives.3.6.HUMMER*