Traveling to Oz from the US is expensive and it can cost anywhere from $1100 to over $3000 usd on a major US carrier. However, a little secret known to only a few is that if you purchase an around the world ticket, the cost is cheaper or the same and you get to travel to as many as five countries for the same price. Around the world fares, known as RTW tickets are created by discount consolidators and typically cost only a little more than a standard round trip ticket to Australia. If you have the extra time, even just a few days, these fares can be worth it, especially if you've always dreamed of stopping in China or Thailand for a few days. Another type of ticket available is known as the circle pacific, a type of ticket that goes throughout Asia, Australia and New Zealand.
My favorite site: Air Brokers International, www.airbrokers.com. Beware though, you can't always buy a ticket online, you may have to do it the old-fashioned way and simply call, or make an email request for a specific quote, but the prices here are worth the extra work and really can't be beat.