Welcome to Gaia! ::

First, I will cover on HOW to use RSS. (You probably already know this, but im covering it for those who don't know)

Simply open up the web browser on your PSP. Find a site thats offers RSS feeds. Select the RSS feed link and click X. The PSP will ask if you want to add it to your RSS links. Click "Yes" and your done. You can now exit the web browser and access your RSS feeds from the RSS Channel in Network.

Note: If you want to stream music from the RSS Channel (Ex. Podcasts) they have to be in .mp3/.aac format.

Now, I assume your looking for links to RSS Channels? 3nodding No problem.

http://boardsus.playstation.com/playstation/board/message?board.id=psp&message.id=1426897

On the Playstation Message boards, they have a thread dedicated to RSS Feeds. Over 9 pages of straight RSS.

You might want to add that page to your bookmarks. :] Quite a large URL.

http://en.wikipedia.org/wiki/RSS_(file_format)

Normally, RSS is used to read headlines of sites that Update constantly. (The sites themselves use XML files I think) But you can actually attach other files to your feed. Which gave birth to podcasting, vodcasting, and a billion other forms of "casting" media.

So far, the PSP only supports streaming audio through RSS. Hopefully, video streaming will be available with another update. (Vodcasting)