Carl Zimmer has been writing about the latest discovery in human evolution. You can read about the details here. Scientists have sequenced the mitochondrial DNA of a 40,000 year old finger that was found in Siberia. Basically what they discovered was that the genetic differences were to great for the finger to belong to our species. But it was also significantly different from Neanderthal DNA as well. Some researchers were quick to point out that there haven't been many genetic studies on Neanderthals so we don't know just how diverse there mitochondrial DNA is. We will have to wait for more testing before this can be settled.
In the mean time, this story reminded me of one of the Creationist arguments about Neanderthals. The typical claim is that the Neanderthals are Homo Sapiens but have some sort of disease like Rickets. Unfortunately in the face of genetic evidence, that argument no longer works. The differences between Neanderthal and Human are too great.