When you go to the "Monetize" tab within your feeds in FeedBurner, the original "Sorry this is not available for you yet" paragraph is gone and replaced with "Activate FeedBurner Ad Network and Google AdSense for Content, and configure how you want these ads to appear in your feed and on your web site."

Does this tells anything?

Wow .. they really integrated AdSense into Feedburner. You can now use the FeedBurner interface to manage your AdSesne for Content ads (AdSense for Feeds not available yet):

http://feeds.feedburner.com/~r/BurnThisRSS2/~3/178077523/adsense_integrated_with_feedbu_1.php

isn't it just regular adsense?
is there anything special about "FeedBurner Ad Network"?

No .. nothing special at all .. just that they implemented AdSense to FeedBurner .... isn't that exciting after all .. but I think it would attract a great amount of new AdSense publishers though ...