Online Travel Booking and Bidding Agencies - Flexi date search; what online tool?

Travelocity had a flexible date search for foreign destinations, but looks like they discontinued it. Are there any other online booking sites that i can use for this purpose?

Thanks..

I personally like kayak.com, it's fast and there are many options and filters that you can use.

Kayak gives me +/- 3days options for the travel dates. I need more than that. I want to see all the available fares and then chose the lowest one that is available. We still have that in domestic travel on Travelocity, but not for foreign destinations any more. :(

You can try www.zuji.com.hk.

Try http://beta.itasoftware.com , you need to sign up but they dont ask any person questions, it shows up to 30 days of fares starting with date you specify.