pic or digitl speed controller for a electronic golf trolley

I am looking in to building a electric golf trolley as a project, i was told that using a pic controlled circuit would be better but not essential, has anyone got any ideas i have looked around for different circuits but i have had no success.

The only criteria is that it has a output of 12V for the motor.

There are tons of PWM circuits to control the DC motors:
http://www.solorb.com/elect/solarcirc/pwm1/
**broken link removed**
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http://www.armory.com/~rstevew/Public/Motors/pwm.gif
http://www.johnnyastro.com/ArcadeChopper/Images/pwm.jpg
http://www.4qdtec.com/images/pwm.gif