WordPress has a pesky issue where it doesn't rewrite relative links in posts (including images) to absolute links in rss feeds. The behavior for the site is correct (I like many strongly beieve in relative vs. absolute links for semantic purposes).
For feeds though, to be correct and validate, they must be absolute. Meaning wordpress should prepend the siteurl to any link,
<a href=""><img src=""> should become absolute.
Has anyone found a plugin? Or a patch to WP 2.0 to fix this?