tedster - 10:30 pm on Nov 16, 2011 (gmt 0)
Google's support of authorship mark-up (it began in June 2011) is considerably more than HTML 101. See Google Starts Supporting Authorship Markup [webmasterworld.com]
There is support for many authors contributing to the same website as well as rel="me" tagging. And not every article that uses authorship markup will see all the benefits, such as author photos in the SERPs.
I suppose you could claim authorship for ghost-written content - however, I wouldn't do it. One thing that Google is going here is building reputations for various author identities. I would suggest that playing it very straight is the best long-term strategy. As usual, YMMV. This is new territory.