normalcdf

Here are some possible suggestions.  I hauled the addresses out of our reference material sticky topic :)

 

z score probabilities - this is great

http://davidmlane.com/hyperstat/z_table.html

Another Stats calculator - More versatile than the first     (Teach yourself Stats site!)

http://stattrek.com/online-calculator/normal.aspx

http://stattrek.com/online-calculator/binomial.aspx

http://www.danielsoper.com/statcalc3/calc.aspx?id=70