Checking out a recent site I've done which has a RSS 2.0 feed, I get the Yahoo "View as XML - Add to My Yahoo!" links. I know that Yahoo is not indexing the feed directly with the regular Slurp, however I have regular visits directly to the RSS feed from YahooFeedSeeker/1.0, as well as visits to the site from Yahoo-Blogs/v3.9 (the Yahoo blog indexing robot [help.yahoo.com]). I use a link element as described by lupatis in the post above as well as a direct link to the feed with a standard anchor.
You might want to check out the official Yahoo guide for RSS publishers: