Thanks a lot for this library. This is exacly what I was looking for.
I use it with 6 differents sets of power RGB leds and your effects are very nice!
For information, my RGB leds are not plugged on pins that provide PWM (pins 2 to 13 on my mega 2560).
So I had to include in your library an other library to make PWM using software (softPWM library Google Code Archive - Long-term storage for Google Code Project Hosting.). I also had to change in your library the "anlogWrite" by "SoftPWMSet".