Try looking for an RSS feed generator over at www.hotscripts.com and www.krugle.org - I'm sure you'll find one there. But make sure you limit your searches to the server side programming language and database system you're going to use (and make sure it's installed on your server). But bear in mind that RSS is used primarily to syndicate content to feed readers and aggregators, so if you're thinking about syndicating content to other Web pages for SEO reasons, forget about it, since the syndicated content will be considered "duplicates" and removed from the indexes at the major search engines (especially Google). In fact, there's even a chance that YOUR pages could be considered to be the duplicates and you may end up shooting yourself in the foot instead (this is one of the main reasons why many sites don't allow people to parse their feeds on other Web sites).
are you using a known cms or a custom cms? if you are using a custom cms, you will need a programming service
if your site is database driven then it is easy to create feed using programming (php,asp,jsp or cmf)