Well you need to have:
1. A good understanding of your whole ignition system and ECU
2. An interface to hook up a computer (ie. laptop) to the ECU for data logging.
3. A EEPROM burner to make your own chips
4. Software to write these chips
5. A whole lot of dyno time for testing.

Im not sure if this is a complete list or not. But this is my understanding of whats involved.

If your serious I would suggest finding out what brand ignition system your car uses and find a book that covers it. ie. VW uses a Bosch Motronic igition system.