I have a greencard, permanent resident's visa.  If I go to Canada and
return to the U.S. Do I need to bring my passport(British... it's
expired you see.
I went to http://travel.state.gov/tips_canada.html and found that I
only need
a greencard to enter Canada but could find no such useful site for the
U.S

Hello and thank you for your question.

As you know, "[a U.S.] Permanent Resident or holder of the immigration
"greencard" needs to present a valid card to the Canadian authorities
when trying to enter. Other than this fact, you will be treated just
like a US citizen and expected to produce the same proof of travel
reason."
http://www.bcis.gov/graphics/hditravelcanada.htm

The test for reentry to the U.S. after a one-time visit to Canada is
simple in your case:  You won't have any trouble being readmitted so
long as you are the holder of an unexpired green card and your time
outside the U.S. is less than one year.
9 FAM 42.22 N2
http://foia.state.gov/FAMDIR/masterdocs/09FAM/0942022N.PDF
[page 3]

I suggest you print out the document cited above and carry it with you
when you go.

Enjoy your trip!


Search terms used:
reentry canada "permanent resident" site:.gov

Thanks for letting us help.  If you find any of the above unclear,
please request clarification.  I would appreciate it if you would hold
off on rating my answer until I have a chance to reply.

sincerely,
Google Answers Researcher
Richard-ga

Thank You Richard,
You got me what I needed quickly and saved me alot of time and
needless frustration on the uselss Government Information phoneline.
Kool..that was my first google question,
Tranqility