Oh yeah, Americans have accents. I can usually pick out an American from the sound of his/her voice. And I don't just mean the fact that they speak in Imperial and pronounce Z as "zee," XD. Though of course this is always easier the further south they are. I may not realize it in people from New England, but if I hear someone from Alabama or South Carolina, it's more obvious. XD
And that American accent is usually one of the hardest ones for me to figure out. I kid you not, most of the time I can understand what someone with a strong Chinese, Russian, or even French accent is saying. But if it's someone from the southern U.S., I often have to get them to repeat themselves. ;_;