What do you have so far? Are you wanting to use hardware to scan actual cards? Do you want a simulated card reader? Does it just need to read the magnetic strip or do you want it to also send data to a credit card service? Your question is tough to answer because there are too many variables with the project outline. If you can create a specific question, you will find more assistance here.
If you are really new to LabVIEW, you might consider contacting an alliance member for assistance. www.ni.cam/alliance