We aren't at war with Islam despite what some claim. We're at war with the Islamic extremists who sponsor and conduct terrorism, both against us and others.

Likewise, we aren't at war with THE PEOPLE of Iraq, just the leadership. We're going to great lengths to keep civilians deaths to a minimum. If we wanted to, we could just carpet bomb Baghdad to kill thousands of people and perhaps take out Saddam. With the turn of a few keys, we could send an ICBM to Baghdad in about 30 minutes and kill a million or more people. We'll do no such thing.

But, as Robert pointed out, we most definitely are at war even if it hasn't been formerly declared by Congress (though Congress did authorize this last year, it isn't the same as a declaration of war). In all US history, Congress has only declared war a handful of times but we've been at war many times.