This year it is 150 years ago that miners in the German Neander Valley lucked upon 16 fossils that turned out to belong to a different homo species. The Neanderthals are of special interest to the study of the homo sapiens brain, being bigger in average volume, but (presumably) different in function. Since brains doesn’t fossile there are really only two ways of studying this difference: (1) through comparing the DNA of the two species, and (2) through what has been called cognitive archeology - the deduction of how the Neanderthal mind must have been organized through an examination of archeological evidence such as diet, technology and social structure.
If you happen to read German this article in Die Zeit kicks off the Neanderthal year. In July Bonn will host a big conference on the Neanderthals. Its web-site has a number of interesting papers on-line.