All right, this also on the CBP website on their Q & A -
How long can I stay in the U.S., and can I go to other countries while I'm in the U.S. on a B1 or B2 visa?

Question
How long can I stay in the U.S., and can I go to other countries while I'm in the U.S. on a B1 or B2 visa?

Answer
B1 and B2 visas are usually issued for a term of 10 years. Each visit may last up to six months, although some categories of visitors may apply to extend their visit for an additional 6 months. During your visit to the U.S., you may visit Canada, Mexico, or the Caribbean islands (not Cuba)for up to 30 days and re-enter the U.S. as long as you re-enter within the period noted on the Form I - 94 which you received when you first entered.

For instance, if you come to the U.S. on July 10, 2005 on a B2 Visitor Visa, you may go to Canada and/or Mexico on or after November 10, and reenter the U.S. any time up until Dececember 10. But because the six month period is up on December 10, 2005, you will also have to depart from the U.S. on that same day to avoid being an "overstay" (unless you applied for an extension of stay.)

If you visit other countries such as England or Costa Rica, then return to the U.S., your re-entry will be considered to be a new admission, rather than a re-entry from a contiguous country in the course of your initial visit, and the admission inspection may be more strenuous. The Officer inspecting you will want evidence that you intend to go back home to your country of citizenship to live as opposed to returning again and again to the U.S. after visits to other countries. Remember, a B1 or B2 visa allows you to come to the U.S. to visit. If the CBP officer suspects that you are actually trying to be a de facto resident, you will be denied entry.

Re-entry is, of course, dependent on your continued eligibilty to enter. If you have been arrested or committed an illegal act resulting in a warrent in your name since the time the visa was issued, you could be denied re-entry.


Now, that should clarify it! Sorry for the multiple posts.