[MTVN]

I actually heard recently that correct English is to spell organize, realize etc. with a 'z' which is how it was first spelt in English. Over time we've started spelling them with the 'ise' ending though and so now we think of the 'ize' spelling as American-English. Doesn't look right with the z for me though so I stick to 'ise'

Here's a blog post on it though: http://blog.oxforddictionaries.com/2011/03/ize-or-ise/