here. The official announcement will be made on April 9th. (Thanks Aaron)
Update (03/28/13): As Slicing Up Eyeballs points out in their story, there's also a leaked magazine ad, too. All of this makes sense, as the announcement is just over a week away, so posters/ads would have already been produced. So, not confirmed by Robert just yet, but you need to be ready for the single day ticket sales. They will go in a flash.
And now the Chicago Tribune confirms that the poster is accurate. Confirm The Cure are playing Lollapalooza.