@brokencdplayer,
The use of the letter 'z' in endings such as -ize, ization, -izing, etc is more common in US English. The -ise, -isation, -ising endings are standard in British English. That is to say, the version of English which is standard in Great Britain, Ireland and the countries of the British Commonwealth (for example Canada, Australia, South Africa, Nigeria)
list here
http://www.execulink.com/~donslau/BC.html
Incidentally, British English speakers call the letter z "zed" whereas US English speakers generally call it "zee".