You need to change the form to be URN-based instead of URL-based.
Two ways to do this:
1. Create your form and send as an attachment. This automatically strips the URL out and is much easier than:
2. Publish as URN-based and copy around. Create a form and when you go to publish, choose "save to a shared folder" on the first screen of the publish dialog. On the second screen, browse to a location and click next. On the third screen, delete the path so that it is completely blank and click Finish. Now, you can e-mail this form to your friends, but you won't have any central way to update them.
Hope this helps!
Patrick Halstead
Project Manager at Qdabra