How to provide a newsfeed for another site?

I'd like to implement a newsfeed, that can be plugged into some web-si开发者_运维问答te: my site/service gets a request from another site with that site's ID (or login/password) and return a newsfeed (html-fragment). The newsfeed is then visible on that site. The tricky part is that after clicking on the news title the news content must be displayed on the site (no redirects anywhere). What is the best way to implement such type of service?

If you can use a scripting language like PHP to provide the RSS feed for the ohter site, then some javascript should be able to handle the display - its all about creating an RSS feed in the correct format.....