there is a tutorial for this in the CMG book by the Meyers.
Otherwise search the net. There are bound to be online tutorials...
Or use Combustion - it has a built in particle system that was used to
create it - very simple
Considering that combusion 1.0 came out in 2001 and The Matrix was released in 1999, I have to doubt that it was really used in the film's production.
combusion 2.0's particle system is licensed from Wonder Touch's Particle Illustion.
The Digital Anarchy plug-in is fantastic. It can do a lot more than just make Matrix strips. It's not very expensive either.
Navarro is correct, DA's plug is definately worth it.
And renders REALLY fast compared to Particle Playground
Thanks to everyone for their professional assistance!
If I remember right Maya was used for the effect ;-)
Maya... yes the web of illustion!
There is a tutorial (or there was) on www.creativecow.net. Its pretty easy...I have a copy of it. I did it for my compositing class last quarter.