You need your US passport, but no visa unless you're planning to stay longer than 90 days! (The State Department has a great website where you can look up other countries to see if US citizens need visas to go to that particular country
http://www.travel.state.gov/travel/t...es_1229.html#g). That, of course, doesn't answer about your husband. He needs to follow the requirements for Mexican citizens---doesn't matter what the US says he is, he will be traveling on a Mexican passport. I went to the Guatemalan Embassy's website (
http://www.unidosporguate.org/visas.htm) and it appears that he doesn't need a visa either. So----happy travels!