This is my tiny but powerful tweaked version of the original autoTangent by Michael Comet (http://www.comet-cartoons.com).
Thanks to him for giving me permission to make this available here.

DESCRIPTION:
Changes selected graph editor keys to be smooth but without overshoot.
Kinda like 3DSMax's autoTangents. The amount of softness can be
user set, so that the tangents will overshoot a little bit if desired.

This also has a built in UI to run all of this and to set the softness.
The softness value is also remembered per session from the last one used.

MY IMPROVEMENTS:
Soften value is now relative to curve and 1.000 is the soothest value without overshoot (next to flat keys)
0.00 is flat and 2 is some kind of overshoot. Also using just optionVars for flatten and soft now,
so the values will be remembered and aTan_smoothKeys(); can be used for a hotkey.
2010/11/01 - minor tweak, deactivated print statements to gain speed (once for debugging)

USAGE:
source "autoTangent.mel"; autoTangent();
u can use the "aTan_smoothKeys();" for a hotkey (without UI) when autoTangent is sourced.