You can use the newslisting snippet to create your rss feed.
So create a new document with a blank template and set the content type to text/xml
Here is an example call for the content of the page:
[!NewsListing?format=`rss` &startID=`18` &summarize=`5` &truncSplit=`false` &levelLimit=`1`!]
The startID is the folder contaiing the documents you want to show in the rss.
Summarize is the number of items to include in the rss.
levelLimit tells the snippet to only look inside the startid folder and not go into any subfolders.
truncSplit will summarize a post
Then in the head section of your template include the following:
<link rel="alternate" type="application/rss+xml" title="RSS 2.0" href="[(site_url)][~29~]" />
this will show the rss link in the address bar in firefox and other supported browsers.
You can also add a link on you page like the following:
Hope that helps.
Kyle