You can configure the Email Receipts feature in a paid level account and the user would be sent an email receipt in plain text that can include the submitted data. This tutorial on setting up Receipts goes into more detail: http://forums.adobe.com/docs/DOC-2664
The user could then print the email that they receive.
Printing the form from the web browser is not supported and does not get good results.
Another option is to take action yourself to "Download Response as PDF Form" for each submission and download the PDF of each users response and email that back to them to be printed depending on your needs, this would require a lot of work on your part. There is a popular feature to be able to include that PDF in the Email Receipt, but at this time you'd need to email that PDF to the user yourself.