Tuesday will typically be the day you can find the best deals on airline tickets. I would try using fly.com or hipmunk.com as they both show multiple airlines and dates at once. Fly.com allows you to compare prices from Hotwire, Priceline, Orbitz, Travelocity and CheapTickets, so you can find some of the best bargains on flights.
Hipmunk.com shows flights and prices in a really unique, but great readable grid panel, which makes finding flights at the lowest price easy.
Travelzoo is also be helpful for checking multiple airlines at once.