Serial to MIDI without MIDI shield

I'm looking for software to convert my data sended by arduino to MIDI messages the computer can work with.

I found http://spikenzielabs.com/SpikenzieLabs/Serial_MIDI.html

I tried there demo sketch but I did not managed it to get to work (the TX light keeps flashing red),

someone hase experience with this software? or know something simular (for mac)

thanks in advanced,

Thyvo

After 3days, noone =(