Hi.
I'm no expert but I am doing exactly this at the moment. I have done it with an Android ioio board and mosfets and now I am doing it with a PIC18F14k22. It has 5 hardware pwm outputs. I used ttl level mosfets driven directly and they can carry a couple of amps. The resistors need heat sinking though but it was easy. I also purchased a 5m RGB LED strip off ebay. It comes with a controller. I piggy backed onto that and that is capable of driving about an amp per channel. Right now I am getting my Raspberry Pi to act as a web server to control the RGB strip for no other reason than because I can. I reckon you should look into the many pics with hardware pwm and build your own drivers.