I've heard that Richard Bett (Johns Hopkins University) is editing The Cambridge Companion to Ancient Scepticism, forthcoming in 2008. So far I only know that he's writing an essay on skepticism and ethics, and that Luciano Floridi (Oxford University) is writing one entitled "The Rediscovery and Posthumous Influence of Scepticism".
I look forward to reading this book, which I'm sure will include papers by several leading specialists in ancient skepticism. In fact, Bett is one of them: he has written a number of papers on ancient (and contemporary) skepticism, published Pyrrho, his Antecedents and his Legacy (Oxford: Oxford University Press, 2000), and translated Sextus' Against the Ethicists (Oxford University Press, 1997; with an introduction and an extensive commentary) and Against the Logicians (Cambridge University Press, 2005; with an introduction).
Edit: for more information about the contributions, see the comment by Jim Hankinson (University of Texas).