There has been some recent buzz at WebmasterWorld that YPN coming very soon. The thread creator used a conference call where Yahoo's CEO Terry Semel, "apparently said that YPN would be rolled out "very soon.""
Nick at ThreadWatch then wrote a thread, Yahoo Publisher Network to Debut in August? In that thread, he uses some logic to determine that it is very possible that YPN will be here in August. The logic comes from the announcement by JenSense about the recent listed panel on the SES San Jose 2005 Contextual track Earning From Search & Contextual Ads. On that panel is an individual by the name of Will Johnson from Yahoo! Search Marketing.