First of all, each computer will simulate a layer. A neuron simulation looks like this

Input Layer(Where inputs such as sensors) are put in as number values
Hidden layer 1(A computer)
Hidden Layer 2(Another computer)
etc.
etc.
Output Layer(Where the output/motor system control occurs)
If you add a new computer/user, it becomes the last hidden layer and the output layer is moved down again. In this way, it doesn't effect the input of already trained layers and learns quickly. Also, each computer will simulate a certain number of layers based on its speed so: a 2GHZ system might simulate 5 layers and 500mhz might simulate 1 layer so that, the 500 won't slow the system down...

I like the idea of people talking to each other "In front" of it. If you help, what section will you help out with? If theres something you can help with that I haven't menchond please say so...