I just have to put this website here. An aggregate of information about travel hacking for people in the US!!
http://www.nomadicmatt.com/travel-tips/travel-hacking-guide/
Websites to check:
http://www.kayak.com/
- an aggregator, but seems to be have its own flight bookings nowadays.
http://www.cheapoair.com/
- i have flown more times than i can count using this.
http://www.vayama.com/
- keeps telling me the flight cannot be found.
http://www.mobissimo.com/search_airfare.php
http://www.momondo.com/
- directs to another travel agent - geekfare.com - which has very mixed and polarized reviews.
http://www.skyscanner.com/
http://www.travelocity.com/
http://www.expedia.com/
http://www.orbitz.com/
