Anyone get midi in to work with a microkorg?

Can anyone got a microkorg synth to communicate to an arduino through MIDI? I have been trying to get midi-in running for days with no luck. None of the sketches that I tried have worked, even the simplest ones with 1 led to detect midi coming through. Im sure the hardware is correct and working properly, when the rx is disconnected and a led between pin 5 and +5v flickers corresponding to keys pressed( Im using kuk's 4n28 opto circuit,http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1187962258/0 w/o the 100k between pin4 and ground.... the led wouldnt flash with it in place) and my arduino loads and performs other sketches with no problem. So I guess that it is either that the microkorg uses a note on w/ 0 velocity message, instead of a note off message( though, the arduino should still be able to detect data coming in, right?) or there is some wrong with the arduino. Physically the board is in good shape, no bad connections or cold soldered joints. I have even tried connecting the opto output (incoming data) directly to the atmega's pin 2 (RX), so I know it was getting there. I have also tried a sequential circuits prophet 600 (one of the very first midi equipped synths) and that doesnt work, though it and the microkorg connect with each other- no problem. here's one of the codes I have tried:

variables setup
byte incomingByte;

int statusLed = 13;   // select the pin for the LED


//setup: declaring iputs and outputs and begin serial
void setup() {
  pinMode(statusLed,OUTPUT);   // declare the LED's pin as output
  Serial.begin(31250);        //start serial with midi baudrate 31250 or 38400 for debugging
  digitalWrite(statusLed,LOW);
}


void loop () {
 if (Serial.available() > 0) {

    incomingByte = Serial.read();
    // wait for as status-byte, channel 1, note on or off
    if (incomingByte==144){ // 144 is note on ch1
      digitalWrite(statusLed, HIGH);
      delay(20);
      digitalWrite(statusLed, LOW);
      delay(1);
    }

 }
}

Im out of ideas.... Im an arduino novice and this is my first experience working with MIDI.....so far I hate it. please, any ideas or suggestions, tips or tricks offered up would be very helpful and much appreciated. thanks