Thank you for your hard work on NextGEN Gallery!
Please note that NGG 1.3.3 breaks RSS in WordPress 2.8. If I deactivate NGG, then my site's RSS feed works fine. But when NGG is active, the RSS feed is broken.
I believe this is because there are perhaps some tags that are not being closed out properly somewhere, and as such the RSS parser is breaking because the content is spilling out into the RSS structure (this is just a guess).