Here's a link to an article from the New York Post, with, as Jihad Watch notes, the first reasonably accurate discussion in a mainstream publication about Muslim honor killings in the United States. It notes: "Over the past two years, there have been about a dozen attempted or successful honor killings committed in the US."
And here, from the comment section of that blog entry, is a German website that lists the known honor killings in Germany. Even if you can't read German, you can easily get the idea just by scrolling through it.
Bottom line: honor killings may be more common in Europe, but they're happening here too.