Christof Koch and Naotsugu Tsuchiya are trying to establish a major statement about attention and consciousness which can be followed up on Scholarpedia which seems to be a great website anyway.
Christof has pointed these things out in Tucson and will also eloborate on it in Taipeh.

I have reluctance against the statement that there can be attention without consciousness, which is an extraordinary claim in my opinion. The evidence they give here can be read in more depth in an article by Jiang et al. . This article by Buschman and Miller may by interesting as well for a discussion.
As this is a huge topic with some history one can also browse David Chalmers collection

Christof Koch and Naotsugu Tsuchiya have published their view and obviously there are important statements from Bernard Baars, Stanislas Dehaene and Victor Lamme to name a few.

The claim that there may be attention without consciousness is possibly stretching the understanding of terms too much in a “lab-direction” which ultimately loses connection with a common and sensible understanding of the terms. I doubt that it is meaningful to say someone attends to an objects when in reality there is only an unsuccessful attempt to attend by looking in the direction of that object. We also have to acknowledge natural limitations: visual attention is obviously not naturally to be performed the way binocular rivalry tests suggest. What naturally happens is a kind of competition between different contents of consciousness and attention. This process of competition has voluntary and involuntary aspects. Research should support an understanding that enables people to be aware and attend to the contents that are relevant and important in their lives and the conditions they are in. Obviouslly both attention and awareness can be distracted, which may be not only unwanted but even dangerous.