RSS Settings and Feeds Link

First, go to Document/Form Library

Go to Settings >> Document/Form Library Settings >> RSS Settings (under Communications)

You can select the fields as shown below.

Update the List and View IDs and the URL should look as shown below.

http://dev.sp2010.com/Infopath/_layouts/listfeed.aspx?List=E5F5F740%2DB5B8%2D440B%2DBA22%2D051127AAA366&View=211E24B2%2D01F9%2D44D1%2DB371%2DED8BD63249D9

You can give the link to users and they have an option to Subscribe to this feed.