How to find lowest airfare...flexible dates
 

What sites or tools do you use to find the least expensive airfare if you have flexible dates...say that you want to take three night trip sometime in November? Most of the airline's sites don't seem to accomodate this.

from a suggestion here i now use www.itasoftware.com .

they have a month long search option that is very helpful.

Sorry, meant to add that I am looking for international flights, not U.S.

Are you able to find open jaw tickets on these sights? My DD and two friends are planning for Europe next summer. The are pretty flexible where they fly in and out of to get the best price. Was looking at Dublin as I know last year Aer Lingus was fairly cheap but it seems higher this year than last. I guess all airfare is that way. I also think they should wait a while to get their tickets but they are anxious right now. This is flying from LAX.

I have pretty good luck with kayak.com and you can do the flexible dates.