Not meaning to offend anyone, here, but this forum generally is used by folks wanting to know how to use the existing features of the News Feed RSS module.  I think your question would get better visibility in the Let's Chat forum. http://www.dotnetnuke.com/Community/ForumsDotNetNuke/tabid/795/forumid/118/scope/threads/Default.aspx

It's a nice feature to have, but the current module won't do it out of the box.  You might also, consider submitting a feature request on the bugtracker site.

For what it's worth, I've seen some folks do it with a modified page control that includes a html marque tags, and you could probably do something like that for it.  Most codebehind I've seen is just doing that type of thing.  The issue with using it, is not all browsers support it.  I've, also, done scrolling with javascript, had a nice asp gallary that scrolled, and did use it in my early DNNv1.9 site, placing it within an HTML module, so it's probably still possible to do, just not out of the box with this particular module.