Brian Dunning has released an app for validating credit card numbers from within FileMaker Pro. Card Validator checks the authenticity of a card number with a single calculation. According to Brian Dunning:
Validate credit card numbers for FREE in FileMaker! Announcing Card Validator for FileMaker, available imediatly. Check the authenticity of credit card numbers with a single calculation, NOT a script, NOT a plug-in. Card Validator is completely free, and itis available now for FileMaker Pro
versions 3, 4, or 5.
You can find more information about Card Validator at the Brian Dunning Web site. Card Validator for FileMaker is available for free.