Here is a channel I created that can play an RSS feed for videos and music that have a Plex URL service or direct links to media files in the feed.
This channel is the RSS Feed section used in my Webisode channel - http://forums.plexapp.com/index.php/topic/71407-new-channel-webisodes/.
The channel can be added through the Unsupported Appstore.
The channel will only work if there is an existing Plex URL service for the website accessed in the feed or the RSS feed includes a direct link to the media file listed in the RSS feed XML code. The channel has a built in function that will check for supported media files in the RSS feed. If there is no URL service or compatible media files in the RSS feed, the feed item will show as an icon with "NO URL Service or Media Files for Entry" as the title.
Latest Updates
1/12/2014 - Updated to fix archive.org issue and require less fields and support more feeds
1/6/2014- Added additional support for feeds with media links
KNOWN CLIENT ISSUES/RESTRICTIONS: Known Client Issues or Restrictions:
Plex/Web (aka Media Manager)
You can view and play feeds on Plex/Web, but since Plex/Web does not support user entry screens, you cannot add new RSS feeds in Plex/Web even with the new version of Plex/Web (http://plex.tv/web/app).
You can currently copy and paste the url address of a new feed you would like to add into the search box at the top of the screen to add the channel. You must be within the directory for the type of show you would like to add. For example if you opened of the video directory which shows all of your currently installed video feeds, then you can paste the url of the new feed you would like to add in the search box of that page. A dialog box will appear and tell you that the rss feed has been added.
The Plex/Web client only updates once daily, so any changes made to the RSS Feed channel plugin will not show up immediately in Plex/Web. So even if you hit the refresh button, any RSS feeds that you add or delete will not be visible in Plex/Web for up to 24 hours. The only way around this is to clear the cache of the web browser you are running Plex/Web on.
IMPORTANT NOTES AND INSTRUCTIONS:
RSS Feeds with Direct Links to Media Files
RSS feeds require a Plex URL service or a direct link to the media files in the XML feed document. A list of websites with a Plex URL service is at https://support.plex.tv/hc/en-us/articles/200690288-Supported-Plex-It-Websites. With the Firefox browser, an RSS Feed with a direct link to the media files will have a title of "Media file" with the media file listed below. Media listed in the XML code as enclosure or media:content URL are recognized by the channel code.The channel can support RSS feed that show a media file of type mp3, m4a, mp4, and flv. Examples of RSS feeds that have media files and provides direct access to the video files are http://thebrowncast.libsyn.com/rss and http://feeds.feedburner.com/techsnaplarge?format=xml. The channel has a built in function that will check the media in the RSS feed. If there is no URL service or media files in the RSS feed, the entry will be listed as "No URL Service or Media Files for Entry,".
Roku Client
Roku users can benefit from using the Remoku remote control (available at http://remoku.tv/) to enter RSS feed URLs and thumb locations with cut and paste.
Additional Notes
Plex/Web has changed their interface yet again, so it does not support a user input screen, the search dialog box no longer supports input, so you must use another client to add RSS feeds. And, as stated above in the Known Client Issues or Limitations, the Plex/Web interface will only update once a day unless you clear your cache. So changes any changes you make to the RSS Feed channel plugin will be seen immediately in other Plex clients but will take a day to show up in the Plex/Web interface unless the cache is cleared for the browser you are using to access it.
With Feedburner pages, you may need to choose the "ViewFeedXML" link to get to the actual RSS feed URL.
For feeds with multiple media choices, the channel uses the default or first version of the media, since this tends to be the best quality. Feeds all use different attributes for media quality and some just use a naming scheme for the media file to denote the quality, so there is no consistent method that could be used to catalog and display the multiple options that may be given for the formats or qualities of media that may be offered by a particular feed.