[Danny Diaz]

First thing you want to do is install NI-VISA. This allows LabVIEW to talk with the serial ports. This also adds the Serial Communication VIs to LabVIEW.

You can find these VIs in the functions palette through the following path:

Data Communication -> Protocols -> Serial

These VIs will allow you to write and read bytes to/from the serial port.

If you need any other help let us know!
-Danny