The IEEE Spectrum has lots of special essays on The Singularity, by both enthusiasts and skeptics:

"Economics Of The Singularity" By Robin Hanson
"Signs of the Singularity" By Vernor Vinge
"Can Machines Be Conscious?" By Christof Koch and Giulio Tononi
"The Consciousness Conundrum" By John Horgan
""Rupturing The Nanotech Rapture" By Richard A.L. Jones
"Singular Simplicity" By Alfred Nordmann

(Via MeFi.)