Here's some presets for making chiptunes.. i generated the waveforms in cool edit pro according to the same spec the NES synthesizer chip is using (including using only 4 bits of depth, etc). You can learn more about NES chip tunes here
Included in this pack are 3 pulse wave variants and 1 triangle wave.
The original NES used 2 channels with pulse, 1 with triangle, 1 with white noise, and one for DPCM samples.
You can hear an example using these presets here: http://forum.image-line.com/viewtopic.php?p=322991