Hi sboyddyn,
It is possible to send a form as an attachment, but not as a PDF. You can install a PDF printer from Adobe and set that as the default printer to generate a document, but attaching it as a file to an e-mail will not be easy. In fact, I do not know how you would do it.
There have been talks of working with PDF files with InfoPath on these forums, so trying searching around a little bit to see what you can find.
Hope this helps!
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge