Originally Posted by AlanB
It should be noted though, that unless the law is changed, come January 1, 2008 you will need a passport from that point on. The airline and cruise ships part of the law take effect this January 1st, 2007, while ground crossings (driving & train) take effect 1 year later.
President Bush is expected to sign legislation this week which would delay the deadline for land border crossings until June 1, 2009.