Done it about 3 years ago, 18 stops with BA, Qantas and their group.
Well worth the money. Lots of things to watch out for though in the small print.
http://www.oneworld.com/
Covered us from Oz to the US, down through Central America to South America. From their to the UK, Russia then onto Japan and back down through Asia to Australia. Could of done more of Europe but already been to most places.