Gimpdome

Well, I found a new fractal program
Not sure if it's completely Open Source though
so i'll stick it here:

newbielink:http://home.houston.rr.com/fergusonsc/Tierazon-v29/ [nonactive]

It's free to download and use
but i don't know if the code is available for modification

For some pretty good examples,
check out
newbielink:http://sophquest.deviantart.com [nonactive]
she's got some really good Tierazon fractals