Since 9/11, aircraft crossing the border are required to be on a flight
plan AND in communication with ATC, either VFR Flight Following or IFR.
When flying across southern Ontario talking to Toronto Center, I was
continually hearing Canadian pilots calling up near the border to get
flight following across the border. That's in contrast to American
pilots, who seem to get flight following the whole way there.

I know this to not be the case when entering the U.S. from Mexico but
perhaps that's just because you have a transponder code. We usually
are not talking to ATC when we cross back into the U.S. but we have a
DVFR open.

I was pretty happy with how easy the handoff was into Canada. When I
entered Canada I was VFR. It wasn't really a handoff but I was allowed
to keep my transponder code and the Canadian controller expected me
(the U.S. controller said FF canceled, remain this code, contact
Victoria). Southbound I was IFR (and IMC) and you couldn't tell the
difference other than the use of the phrase "decimal" rather than
"point" when giving freq's.
Landing at Vancouver Int'l was really a piece of cake. The controllers
were very friendly when I told them I didn't know any of the locations
they were talking about (I never saw any "coal mines", etc on the
charts).
-robert