Here is a software tool (spreadsheet) that converts surface deflection expressed in inches to degrees:

[link=http://www.aeroperfect.com/degree.html]www.aeroperfect.com/degree.html[/link]

And two spreadsheets that aid in programming Hitec Digital Servos:

[link=http://www.aeroperfect.com/program_off-plane.html]www.aeroperfect.com/program_off-plane.html[/link]

[link=http://www.aeroperfect.com/program_on-plane.html]www.aeroperfect.com/program_on-plane.html[/link]

While these are "online software tools", they're not tools for calculating aerodynamic design factors in the strict sense. While they are useful, they may outside what you had in mind. If so, please feel free to remove this post