I would like to use rss feeds of some targeted-websites and import them into my website? my question is where and how can I find their rss addresses especially they don't seem to mention it in their pages but I know at least some of them have rss feeds?
The easiest way to check would be to look in your browser's address bar. If you see an orange icon with what appears to be radio waves broadcasting from the lower left hand to upper right hand corner, the site/blog has an RSS feed you can subscribe to. Many (if not all) browsers that support Web feed detection in this manner will allow you to subscribe to them, or at the very least take you to the XML document so you can view the content (or the source code).
which means, if there is no such orange icon in the address bar that means there is no way to get rss feed from that site, please correct me if I am wrong? Note: this was very nice explanation from Dan Schulz!, thank you.
For the most part. Some sites don't include the required code inside their <head></head> tag sections to alert the browser, so if it's there but the browser can't find it, it's the site owner's (or developer's) fault.