The rumors are true. Google AdSense ads for RSS feeds are coming next week. The ads will be contextual and CPM based. You’ll be able to manage your RSS ads via the regular AdSense dashboard.
Google will initially experiment with only a small group of AdSense publishers but will eventually roll-out the program to all AdSense and FeedBurner customers. See existing screenshots of RSS ads.
Contextual, CPM Based AdSense Ads for RSS Feeds Are Coming - Digital Inspiration | FAQ | RSS 