It is really not that simple. The legalities of syndicating RSS feeds are unclear. Here is a great article that delves into the issue:
http://www.feedforall.com/rss-copyright-debate.htm
Once you sort out the legalities displaying the RSS within your HTML website is not difficult. The easiest/best way to do this is to use RSS2HTML a free PHP script. This means that you can retain the complete control of the HTML layout (using templates) and make it match your existing design. Additionally using PHP rather than JavaScript will mean that search engine spiders can "spider" the contents of the RSS feeds.
Additional details and a free rss2html download is available at:
http://www.feedforall.com/more-php.htm
Additional information and other options for displaying RSS feeds can be found at:
http://www.rss-specifications.com/di...-rss-feeds.htm
HTH