Hi,
Have you checked out the USRP examples (check out the examples folder under the NI-USRP entry in the start menu)? This may give you a better idea of where to start or at least help narrow down your question a bit. If you can provide some more specifics of your application it would be easier to determine if there is a similar solution that you may be able to start with.
James K.
National Instruments
Applications Engineer