Research

The most famous research on Binaural Beats is this Oster article:
Oster G (1973). "Auditory beats in the brain". Sci. Am. 229 (4): 94–102. PMID 4727697.

The most recent article on Binaural Beats can be found here:
ahbeh H, Calabrese C, Zwickey H (2007). "Binaural beat technology in humans: a pilot study to assess psychologic and physiologic effects". Journal of alternative and complementary medicine (New York, N.Y.) 13 (1): 25–32. doi:10.1089/acm.2006.6196 PMID 17309374

Here is a University Thesis which reviews the most recent Binaural Beat literature, it was done by a Stanford student.
Review of Binaural Beat Literature (pdf)

For a very comprehensive list of Scientific Articles on Binaural Beats see this WikiPedia Page