Hacker on a Private Language Argument: A critique by Philip H. Thonemann of an account by Hacker of the use Wittgenstein makes of ostension in his private language argument.
Wittgenstein on Rules and Private Language: The `ultimate homepage' by John Humphrey. A comprehensive and critical survey of Kripke's book by the same name. Its aim seems to be to finish off Kripke's position in that work.
Wittgenstein sans The Private Language Argument: Stephen Thornton argues that the private language argument is less important to Wittgenstein's broad conclusions in the Investigations than is commonly taken to be the case.