Hi Jermimiah and welcome
You can have the form submit to the email address for the SharePoint library but this requires enabling email submissions to SharePoint libraries which means setting up Exchange on your SharePoint farm.
People will need Outlook to send an InfoPath form to an email address. But, if people have InfoPath installed, there's a good chance they probably have Outlook.
Another option would be to setup an extranet anonymous page where they can submit forms to and then have a workflow copy the forms to the internal library.
We also have a Web service that you could use which takes an InfoPath form XML and forwards to an email address. This Web service is free but you would need some consulting time from us to set it up.
Good luck,
P