We went to Oz in April this year, but as we planned it 18 months ahead what I did was keep looking at the various airlines websites as if I was booking in for the year before (if that makes sense!). So, if I had been booking for April 06, I found the best deal was with BA in Sept 05. So in Sept 06 I booked for Apr 07 (I'd still been checking the prices in between) and this worked out perfectly as I never saw the price lower than what we paid after we booked them. (Hope that all makes sense!)