One of the questions I received during my trip in Spain was how Google handles duplicate content across ccTLDs, localized domains.
Now I see the same question posted in a WebmasterWorld thread, where Tedster answers it dead on:
No negative effect. Matt Cutts has re-affirmed this, even recently. Localizing the language idioms in your content, currency names and so forth - that is the only piece I'm aware of.
Yes, Google's Matt Cutts answered it and I played the video at the workshop at ISDI - here is Matt's video:
Forum discussion at WebmasterWorld.