I came across this little advertised feature of Facebook while poking around in my Flickr account (at least, little known by me at the time).
To add feeds from other sites to your Facebook account :
1- Open your Profile in Facebook
2- Click on Options (under the Share button)
3- Click on Settings (same location at Options)
4- Select one of the applications listed and fill in the requested user ID / URL information.
Apparently, Facebook share the same short sighted approach as Movable Type Action Streams and supports only one account of each kind – that is, you can only register one Flickr account, one Blog feed with RSS, and so on… Too bad for people who own more than one account.
Still … it seems to be working nicely. I have seen updates to this blog and to flickr pop up on Facebook.
Note: If you are looking for the same option in flickr, open your flickr account, click on Your Account and select the ‘Extend flickr’ tab. The facebook link is at the bottom of the page.