I've figured out how to make an output pin (P0.7) send a square wave through a general purpose transistor to a speaker to make a decent tone. Any pointers on how I can develop an octave or two of notes so I can play a tune??

 

Here is a link to the definition of an ocatave and the frequencies - http://www.techlib.com/reference/musical_note_frequencies.htm

 

Check out a sample code here:

http://embedded.leongkj.net/js08/02_tone02_312.c