One of the features in a Paid level account is "Email Notifications" which work with both web and PDF FormsCentral forms. Notifications
can be configured to be sent to you and/or collaborators and colleagues. There are also Email Reciepts that can be sent to the form filler (an email field on the form). The form data can be included in a text list of fields and answers, the PDF itself is not attached to the Email.
You note "a PDF web posted formscentral", I wasn't sure if I should take that as that you are posting a FormsCentral PDF on a web site to be filled out, just in case I wanted to point you to this FAQ recommending you have users download the PDF and fill out in Adobe Reader and do not embed in a web page to be filled out in a web browser: