The New York Review of Books has a lengthy piece on Martin Heidegger's Black Notebooks. It is worth reading both in terms of being a good summary of Heidegger's philosophy, as well as a sensible take on his rather problematic political views.
This article confirms the sense I have gotten from the previous rounds of reviews of the Black Notebooks, that Heidegger's association with National Socialism run much more deeply than his defenders care to acknowledge.
As I have said before, it is not uncommon for well-regarded philosophers to have any number of unfortunate and backwards social and political views. In these cases, one can either toss out the philosopher's entire body of thought, or try to pick out and salvage the bits that can be identified as untainted by the more unsavory bits of his (because, let's face it—it is always a "he" in these cases) beliefs.
In the past, I have tended to think that there was probably enough salvageable in Heidegger's work that it was worth the effort to figure it out. The more of this stuff I read, though, the more I become convinced that we ought to just toss it all out the window. Dude was a Nazi—end of story.
And again I will say, Heidegger does himself absolutely no favors by deliberately writing in the most obscure language possible. Whatever inclination I might have had to sort through his writings to try to figure out where the fascism ends and the interesting/useful philosophy begins is quickly exhausted by the fact that his language is so inscrutable.