@Eli B- The Yellow wires and the purple are the same mod. I just re-drew the wiring so that it is more clear where to wire the switch. 

@Noise_ToyMan_BR. I would recommend anything by forrest Mimms. His book "getting started in electronics" is a good first electronics book. http://www.amazon.com/Getting-Started-Electronics-Forrest-Mims/dp/0945053282
I've heard Nic Collins Hand Made Electronic Music book is really good too.
http://www.amazon.com/Handmade-Electronic-Music-Hardware-Hacking/dp/0415975921

@Garret. I would check out the books listed above. I've never worked on a micro Korg. I would advise against "bending" it unless you really know what you're doing. The MicroKorg is a very cool and relatively inexpensive synth. I imagine they had to cut lots of corners to keep the price down. I imagine the construction and circuitry are fairly delicate. There may be some interesting bends or mods in there, but I bet it's minimal.