Unfortunately, there is no way to communicate directly with a USB port before LabVIEW 7.0 and VISA 3.0. With the new releases, there are functions called "VISA USB Control In" and "VISA USB Control Out" that give you direct access to a USB port.
You can definitely communicate with DAQ, Serial, or GPIB devices that are connected through a USB port, though. This is done seamlessly through the NI-DAQ, NI-Serial, and NI-488.2 drivers.
Luke S.
