This openFrameworks addon makes it slightly easier to create particle systems in GLSL.
N.B. Does not work in OF 0.8 due to a bug with ofFbo...
openframeworks/openFrameworks#2687
To fix it you can comment out the following line in ofFbo.cpp...
settings.numColorbuffers = settings.colorFormats.size();
Coming soon, for now, see example.
Add in functionality to use programmable renderer in addition to stone age OpenGL.