Hexcel has a some nice calculators.
http://www.hexcel.com/Resources/Calculator
Resin Bleed Calc.
http://www.hexcel.com:82/calculators/src/BleederAidcalcs.aspx
Composite properties
http://www.hexcel.com:82/calculators/src/CompositeProps2WithBleed.aspx
Cured Ply thickness
http://www.hexcel.com:82/calculators/src/CPTCalculator.aspx
Please post other calculators that you know of.