This poll from American Research Group is the first non-partisan poll I’ve seen where Bush’s approval rating goes below 40%.  I expect to see more.

Overall, 36% of Americans say that they approve of the way George W. Bush is handling his job as president, 58% disapprove, and 6% are undecided.

Bush job approval	Approve	Disapprove	Undecided
Aug 2005	36%	58%	6%
July 2005	42%	52%	6%
Jun 2005	42%	53%	5%
May 2005	43%	51%	6%
Apr 2005	44%	50%	6%
Mar 2005	47%	48%	5%
Feb 2005	49%	45%	6%
Jan 2005	51%	44%	5%
Dec 2004	50%	45%	5%
Nov 2004	51%	43%	6%
Oct 2004	45%	47%	8%
Sep 2004	45%	48%	7%
Aug 2004	43%	50%	7%