I was wondering if react particals are in blender 2.5?
I have been looking for them for ages.
I have seen something called partical insance is this anythng to do with reactor particals?
No Particle Instance is a modifier already present in 2.49.
Reactor are mentionned in the TODOS:
http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Particles.2FHair
A new branch dedicated to particles has been recently created.