Via Atrios (I think), a poll has been released that gives a state-by-state breakdown of Bush's approval ratings.
There are a few mild surprises. Texas, Dubya's home state, only gives him a 50% approval. A few red states give Bush low numbers - Nevada (38%), Ohio (40%) - and some of the blue states approve of Bush at startlingly low rates - New York (33%), Vermont (32%) - though I have no idea whether or not those numbers are historically typical for presidents in states they didn't win.
Bush's highest rate of approval comes from Utah (63%) followed by Nebraska (60%).