Les, Any of the sound cards that are compatible with Windows will work with LabVIEW. Some of the top brands are: Aopen, Chaintech Inc., Creative Labs, Gainward/Card Expert, Guillemot/ Hercules, M-Audio, Turtle Beach/Voyetra, and Zalman Tech Co. Any of the cards from these companies with stereo microphone inputs should work for you. The particulars are up to you.
If you are looking to do really high-end stuff with a lot of flexibility, you could look into purchasing one of our <a href=http://www.ni.com/dataacquisition/>DAQ boards</a>. Any one line on these boards competes with the best of the sound cards, but provides more lines and much more flexibility and functionality. Hope this helps, and have a great day! Robert M Applications Engineer National Instruments
