My parents came with us over Christmas with less than 2 weeks remaining on both of their passports, despite my utter horror that they hadn't renewed. My mom insisted "why do they give you an expiration date if it's actually expired 6 months before the date???"
I figured we'd just go to St. Croix or the Spanish Virgins if they wouldn't let us in but they didn't even bat an eye. I don't think they even look at the date. <img src="http://www.traveltalkonline.com/forums/images/graemlins/Tonguea.gif" alt="" />