USB communication from C#

Hello, I am relatively new to programming in .net, and with C#.

I have a prolific USB-RS232 (UID 067B, PID 2303) and a Parallax STAMP II device which I would like to communicate with.

I cannot for the life of me figure out how to communicate with the STAMP from C#.

I have been looking at Jan Axelson's work on USB, but that is very old work, and most is based on HID, of which the prolific doesn't count.

Can anyone provide some insight on how to open up a port with this device, send a couple of bytes and close the port?

Thanks!