Electronic Based Halloween costume idea

I was loading up The Sims 3 and got hit by a BRILLIANT costume idea. I know that I want to use a PIC uC to control it. I was recommended to use a RGB LED and the PWM of the pic to change the Plumbob color between Green, Yellow, Yellow-Red, and Red. But I am TOTALLY unfamiliar with the techniques to control the PWM and how to send the output of the PWM to the LEDs to change the Sim plumbob's color. I'm a little familiar with using Flowcode, but I'm wanting to ease away from that program. Can anyone help me get a good start? I DON'T want ANY code just suggestions to help me get started. I want to figure this out for MYSELF, like I did with my first program that I created using Assembly, that I got to work in simulation but never actually created a circuit for.


Edit: I've started a program using Flowcode, as much as I hate to. But how would I output the PWM to my RGB LEDs? I can put in boxes that you can put in C Code, but I just want to see how to before I use that.

Use 3 o/p pins and a counter, the counter increments with the chip clock, set a pin high theb compare the counter with the req pwm, when the pwm counter exceeds the req pwm clear the o/p pin.
You wont get massive resolution, probably 7 bit at around 30 - 40hz.

You can get 2 pin rgb leds with a built in sequencer.