The NI-DAQ driver provides an API for C, C++, and Visual Basic. It is free, and it will perform all of the low-level register programming for you. NI-DAQ will also install examples so that you can access the full functionality of your board that you may not otherwise be able to use when register level programming.
You can download and install NI-DAQ from the Drivers and Downloads section of ni.com.
Regards,
Erin