[Swing Swang]

Benton - cages might be more humane, but you've still got to kill them once you've caught them (as it's illeagal to release them elsewhere), so you might as well use a trap that kills them immediatley to start with.

This rat trap on a 'low tech site' would probably be illegal to use in this country but it make interesting reading:

http://journeytoforever.org/at_rattrap3.html

The home made wire 'Chinese' trap would be an interesting project, and legal to boot:

http://journeytoforever.org/at_rattrap1.html