REGEX Question

[Antivirus]

I've been trying to write a REGEX to handle either US or Canadian zip codes. US Zipcodes is easy, however how do I validate a canadian zip code, and is it possible for the regular expression to check that the entered data is either US or Canadian format?

Format for US zipcodes is 5 characters, numbers only - therefore my regex for US zipcodes is: /^[0-9]{5}$/

Format for CANADA zipcodes is a little more complex, (# = number, and L = letter) and like this: 3 digits (format L#L) then a space then another 3 digits (#L#). Anyone able to get this done, and is it possible to do it with an OR therein?

This is to be used in vbulletin custom user profile field.
Thanks