I wanted a couple of my views to offer RSS feeds. It's really simple.
Go to Administer - Views and click edit next to the view you want to add an RSS feed. Then setup an Argument: RSS: RSS Feed Selector and make sure it set to "Display All Values" and that's it.
The full instructions are at drupal.org, but it took me awhile to find them:
The node says it's for 4.7, but it works just fine in 5.1