I found a quite nice collection of option tools if you want to price options in your own Excel spreadsheet (Windows only, no Mac) It's an Excel Addin and comes with plenty of (sample)sheets how to use the formulas in your own spread sheets and tools (spreadsheets)
http://www.hoadley.n...ons/options.htm
I particularly like and use the 'Option Strategy evaluation tool' (described here) which lets you price up combos and shift vol and time to expiration, lets you do probability and STDEV analysis (based on IV though) and a number of other gimmicks.
Probably not for you if you are a total Excel or option newbie. But a great set of tools for the intermediate+ user. The free version has quite a few tools but for the best stuff you need to purchase the full version (132 AUD ~ 135 US$, one off fee no subscription etc. needed)
I'm in no way affiliated with these guys, just like the tool.
Marco.