Oleg Bayborodin, the main developer behind Particle Flow, will be showing a new Max plugin titled Particle Flow Tools: Box 1 during SIGGRAPH. Particle Flow Tools is a set of operators and other software tools to extend and improve Particle Flow capabilities.

(continued...)

The Particle Flow Tools: Box 1 operators come in three basic categories:
Groups: Organize and categorize particles within the particle system. These include Group Operator, Group Selection, and Split Group.
Painting: Interactively place particles exactly where you want them. These include Particle Paint, Birth Paint, Placement Paint, Birth Texture and Mapping Object.
Utilities: Speed you work flow and extend Particle Flow’s capabilities. These include Particle Flow Utility, Utility Operator, Preset Flow, Initial State and Lock/Bond.

For more information, take a look at a snapshot of the UI and visit Turbo Squid.