For the ones that dont know thats PWM it Pulse Width Modulaton.
Its aculy making an freq. but the duty cilce is changing so for 30% motors power you switch on for 30% for the time on then off for 70% of the time.
I wod recomed mikroBasic programing language for newbys.
**broken link removed**
Its easy to leran,reqires litle lines of code to do somting,realy nice libarys for LCD,Sound, EEPROM,CompactFlash cards...
if you alredy lernd asembely i wod recomedn stiking to it but if you dont know any programing language i wod recomed basic