It looks like I lost a book or two from my wishlist as well.
I suspect it's not just fictionwise that's seeing some glitches from the change. I spent a chunk of yesterday,March 30, trying to buy Silver Borne by Patricia Briggs. I know it showed up in hardcover, and Amazon had it for $9.99. Mobipocket and Diesel had it for $24.99, but nobody else did. The publisher is Penguin. Under the assumption that they're just holding it back until after April 1st, I went ahead and got it from Amazon this morning while I still could.