It's free. http://www.geocities.com/richgetze
I calculate a deflection of .31 inches at the center of the beam with a load of 4000 lbs. That's for an S10 x 25.4 beam. The beams in BeamBoy can be selected from a list of standard beams, or you can specify your own. S10 x 25.4 means that it is 10" deep and weighs 25.4 lbs per linear foot. That is the lightest 10" beam I saw listed.
Ken