Just so I don't forget it, here seems to be a roll-up of all casualties, hostile and non-hostile, in Operation Enduring Freedom and Operation Iraqi Freedom. I'd love know why this is so damned hard to Google.
Note that hostile wounded in action in Iraq is 30,182, while hostile killed in action is 3323, with another 753 non-hostile deaths. But there are some weirdnesses here: Of the 753 non-hostile deaths, we have 4 listed as "artillery/mortar/rocket", 17 listed as "explosvie device", and 180 as "gunshot". I suppose these could be training accidents, but it's certainly weird to list them as "non-hostile."
According to Stars and Stripes, 1,072,691 army, navy/marines, air force, and coast guard personnel have served in Iraq. That yields a 3% chance of being wounded during hostilities and a 0.4% chance of being killed in Iraq.
In contrast, 2,700,000 Americans served in Vietnam. (I haven't vetted this source, but the number seem right based on my recollection.) 313,616, or 12% were wounded (presumably this is both hostile and non-hostile), and 47,072, or 2%, were killed in action. So the chances of being wounded in Iraq are a factor of 4 lower than they were in Vietnam, and the chances of being killed in action are a factor of 5 lower.
One last little tidbit: The US Army Combat Readiness/Safety Center says that deaths from accidents are running at about 50% of deaths from combat.
Pardon my callousness (please insert all politically correct, pro-forma expressions of my heartfelt concern for the troops here), but isn't a war where you're only twice as likely to die in combat as you are in an accident a pretty safe war?
UPDATE 6/12/08: It looks to me that odds of dying in a motor vehicle accident are about 0.08% over five years. So your odds of dying in action in Iraq are only 5 times greater than your odds of dying in a traffic accident.