It's been in beta for years now. Are you sure it was something current you read?

The Yahoo program has it though. If you can get in there, you can add it to your feeds.

They have had it for a long, long time.

Go to adsense setup.
Click on Adsense for Feeds.

You get the setup page. You have to add each blog.
It's at the bottom. It will say burn new feed.
(There is a help guide)

The cool thing is that the rules are different than content.
You can have an ad block after each item. Very cool to see
30 posts and 30 ads on one page (or more). Of course you can tweak it
differently.

My blogspot blogs were added automatically when I chose the
adsense option on blogspot. These blogs then show up on the feeds
in my adsense for feeds.

Paul