A couple years back I went to a seminar about traveling the world for next to nothing. One of the recommendations the presenter gave was in regards to finding cheap flights. Have you heard of ITA Software? If not, check it out!
ITA Software technology is widely used by domestic and international airlines, online and traditional travel agents, corporate and government-managed booking tools, global distribution systems (GDSs), metasearch services, leisure packaging systems and technology providers. Type in your To and From info, and ita software scans dozens of airlines to give you the best prices.
http://matrix.itasoftware.com/
I must say however, that I have still found better deals on places like www.cheaptickets.com. It always depends. I recommend scanning several different sites and comparing prices. ITA Software is just another good resource to compare prices with. 🙂