Well, you can set the submit button URL action to point to a mailto: url, but this is unreliable, since not every client has defaul e-mail software installed or setup correctly, and the PDF form will fail to submit to the intended recipients.
Instead, you should submit to a Server-side script (ASP.net/PHP/CF) to bypass the client-side e-mail software. The script can send using SMTP w/o client-side e-mail software.
If you are using an ASP.net web server, check out www.PDFEmail.net for more information.
For online examples:
http://www.nk-inc.com/software/pdfemail.net/examples/
