Is there any website/service which will enable me to add RSS subscription to any website?
This is for my company I work. We have a website which displays company related news. These news are supplied by an external agency and they gets updated to our database automatically. Our website picks up random/new news and displays them. We are looking at adding a "Subscribe via RSS" button to our website.
Your question is a little difficult to understand. Are you trying to generate the RSS for others to consume, or are you trying to consume someone else's RSS?
If you are trying to generate your RSS feed for others to consume you will need to read the spec:
http://cyber.law.harvard.edu/rss/rss.html
If you are trying to consume it, that link will also help. Then you'll need to look into an XML / RSS parser.
If you can provide more details I can update my answer.
Write a webhandler that exposes the content of the database as an RSS feed.
If you have the data in your database, creating one yourself is fairly straight forward - there's a simple tutorial here.
Once you've set up a feed, in the <head> of your page, you put text like:
<link rel="alternate" title="RSS Feed"
href="http://www.example.com/rss-feed/latest/" type="application/rss+xml" />
This allows the feed to be "auto-discovered" by your user's browser (e.g. the RSS icon appears in the address bar in FF).
If you are not in a position to add an RSS feed to the existing site, see Page2Rss as an intermediate solution.
You either need to roll your own, or get a service that is a screen scraper.
After you have created your feed, you can use something like Feedburner to disseminate it.
Here's an article that discusses various webscrapers that will generate feeds: http://www.masternewmedia.org/news/2006/03/09/how_to_create_a_rss.htm
If you don't care to click through, here are the services the author discusses:
Other webscrapers suggested in the other answers:
However, you're probably better off generating the feeds yourself from the info in the DB.
If you happen to be using ASP.NET, you might want to check out the ASP.NET RSS Toolkit. It's useful for both generating and consuming feeds.
Actually this is very doable with Yahoo! Pipes. Assuming that 1) your page is under 200k, 2) your robots.txt file does not disallow Pipes, and 3) your news feed has a unique ID, like so:
<ul id="newsfeed">
... you could use the Fetch Page module, trim it to just the items inside the news feed, loop though each list item, and use an Item Builder module to mangle the relevant bits as a proper RSS feed. Then, in the head of your document, you'd put in an RSS link, like so:
<link rel="alternate" type="application/atom+xml" title="News Feed" href="http://pipes.yahoo.com/your_pipe_id" />
This is of course completely ass-backwards, but would work for a quick fix, or in situations where you had no control over the body of the page.