As I'm not from the States and so read and hear different news to yourselves, here's my take on it :
You are not hated as much as you think.
Sure, there's people in certain parts of the globe who would try and shoot someone dead as soon as they heard they were an American, but they'd probably have done that two/three years ago before all this started, because they've been brought up all their lives to believe America is the enemy. Even if Bush suddenly turned around and withdrew all the troops and promised to give every Iraqi a million dollars each, they still probably hate you because that's all they know.
As for most of the world, while many don't like Bush and will gleefully take the p*** out of him, Cheney, Rumsfield et al, it hasn't really affected what many people think of Americans - we DO make a distinction between your nation and the administration in charge.
Even the French (who if your TV coverage is to be believed, every American loathes with every fibre of their being) don't hate Americans - they just don't agree with your politics.
If you're asking this question as in, will this war increase the chances of some other madman trying to do antoher September 11th on American soil, then I'd say possibly, yes. Although with heightened US security, the chances of it succeeding are a LOT smaller.
But if by the question you meant, if I travelled to a foriegn country tommorrow, would I be insulted/ridiculed/hated/abused/whatever just because I'm an American, then I'd say NO. And if you were, then the person who does that to you is severely lacking in IQ (and possibly some other key areas). Just don't get into a debate about politics!