> Does anybody know how to wire a midi in on to the arduino.
>

See the attached schematic. The Rx pin is whichever digital input on the Arduino you are using. The two MIDI wires are pins 4 and 5 of a DIN-5 connector. You must not connect the ground (shield or pin 2) from the MIDI cable. R2 and D1 are there to let you see the data as it arrives by flashing the LED, so they're not essential.

Martin