www.hoadley.net/options/BS.htm
The Black-Scholes model, the binomial model, and other pricing models used in the valuation of options may be found here.

www.optionsclearing.com
Click on the Learning Center link at this site for information about options or futures.

www.hoadley.net/options/calculators.htm
www.numa.com/derivs/ref/calculat/option/calc-opa.htm
www.schaeffersresearch.com/streetools/?click=menu
www.optionsxpress.com/toolbox/index.aspx?sessionid=0
These sites offer options analysis and calculators.

www.optionanimation.com
This site offers graphical analysis of the Black-Scholes model and an implied volatility calculator.