IANAL but...
the Control of Weapons Act and its associated Control of Weapons Regulations in the state or territory you are going to would be the document you want to read. I'm pretty sure that they've been updated in 2001. AFAIK a knife is classed as a controlled weapon if it is used in a fighting context, so you cannot carry it for self defense. Legitimate carry reasons include "professional reasons" so if you are going to use it to cut carrots or rope or if you are a martial artist going to or from a class you should be ok. However the moment you pull it out for any non-legitimate reason, it magically turns back into a controlled weapon.
AFAIK No double edged knives are allowed, except oyster knives which must be less than 10cm long.
I know it doesn't apply to you but I recall that nonmagnetic/nonmetallic knives aren't classed as knives but are strictly prohibited weapons. Even if the "proscribed weapon" is a ceramic kitchen knife.
I haven't seen locking knives that are more than 11cm long for sale.
I've only ever seen one automatic knife for sale, and that was at a flea market knife stand of dubious legality over 7 years ago.
If you want to send a knife home, be wary of using regular postal services because packages are routinely opened, and contents sometimes seized and displayed on the 5:00pm news.
I used to open my mail and cardboard boxes with a humble spyderco delica, but I've stopped taking that to work now, since they've given us stanley knives (box cutters) to use and having two knives attracted too much attention.
It's almost getting to the point where
http://www.banscrewdrivers.com/index.htm might need a humour disclaimer lest people take it seriously.
