I agree with Taja, check directly with the airlines. Expedia, Travelocity, etc. have been going downhill for awhile, and just-as-good, if-not-better deals can be found directly most of the time. Plus, they usually carry additional restrictions when buying through brokers like that (change fees, etc. are generally higher or non-existant).
N.E.D.
PS - happy 500th post, Taja!