New laws affects international travel!
I was caught off guard. I am hoping to keep you from being caught off guard too!
The laws regarding travel to our closest neighbors have changed and become more complex. As of January 23,2007, you are now required to have a valid passport when flying into the US from Canda or Mexico. This also is true of the Caribbean.
You can get a passport from many places, but I suggest you do not fall for the "Fee" for passport services out there like I almost did. I found that you can get a passport from a local passport office about as quickly as any service and it doesn't cost extra. You just have to be willing to take the time to make an appointment and go TO the passport office in downtown Houston.
Those people who are driving or going by sea will have to have their passports by Jan 2008 unless congress adopts new legislation which changes that date.
Here is a link to the Houston Passport Agency:
http://travel.state.gov/passport/about/agencies/agencies_908.html