The source of the firmware I created is downloadable. It's licensed under the GNU GPL. A hex file is included for the people without a assembler. If you want to meddle with the source, take care, the circuit described here is smokable by software: if you open T1 continuously, it and L1 might overheat, if you allow the voltage over C1 to go over the value it's specced for, it may explode. The software and the rest of the information on this page is without any warrantee on my part and for your own risk. However, if you use your brains and a current-limitable power supply for testing, not too much should go wrong.
If you still want the source and aren't scared away by the previous paragraph, it's downloadable here.