From the Adobe FormsCentral forum, this discussion came up recently.
How can I allow possible registrants to fill our a form on facebook?
Does anyone know how I can allow access to this form to anyone on Facebook or by email?
FormsCentral allows you to create both HTML and PDF forms but in this post I’ll just cover how to do this for HTML forms. If you need to do this with a PDF form, check out my blog on How to upload a PDF file to Facebook. FormsCentral also allows you to embed HTML forms (not PDF forms) but you cannot use the embed code in Facebook.