Rany Jazayerli has a free article today at Baseball Prospectus concerning Charlie Haegar, a young knuckleballer in the White Sox organization.
Like Rany, I'd greatly despair the extinction of the knuckleball; although there have been various hangers-on here and there (Steve Sparks, Jared Fernandez etc.), Tim Wakefield has been a lone soldier for about 10 years now, and he is on the other side of 40.