Assuming rss is required, the following results were found.

RSS for the rest of us
If you see an RSS (Really Simple Syndication) icon like this  on a web page, it indicates a feed of updated items that you might want to monitor. Unfortunately, your browser may handle these feeds in a way that I find is less-than-useful - I prefer to...
RSS in Firefox - let's use Thunderbird instead
For some reason Firefox doesn't offer Thunderbird as an RSS reader, which means you have to manually add each RSS feed to Thunderbird. It's not a big problem, but it's still annoying. We can fix this.

Results 1 - 2 of 2