You can also supply $pm->finish() with a parameter. I use it on my monitor scripts to keep track of how many successful connections to servers I've made. I return 0 for failure and 1 for success, so I just add them up and get 'X out of Y servers'. Works perfectly.

I don't know if you can return more than a scalar offhand, but if you could return any type of variable (array/hash/etc), it could be very useful for communicating between a child and parent process. It just doesn't help at all with child->child communication.