I'm Italian so sorry for my (bad) English

I have to do a race timer but I want controll it in the winform app, through the USB, and by photocell. For Example if I press a button (in the application) the timer have to start, and in the WinForm app I have to see the time of the lap, because I have to put the timer in a huge monitor for horse races.
So with this application I can "save" all the time about all runners od the race, and I can dwaw up a standings, and the audience can see the standings in the monitor.
What I have to do is to communicate to the NetDuino through the winfor application, and the NetDuino have to transmit the data in the application so I can save and show all the information about the race, and, of course, show the chronometer about each lap.
I have already understand that the last version of Microframework (sdk 3.0) supports the USB communicating protocol, but because I'm a newbie I want some help an guidelines about the argument, and, If possible, some example codes.
I apriciate your help,
Thank You!!!