A couple weeks back, I wrote a post named Google Says Using Google Translate Can Be Against Google's Webmaster Guidelines. The post drove a lot of comments, because I kind of wrote things there to drive it. I basically said Google doesn't find their own translation worthy enough and if you used it, Google would potentially penalize your site.
Google just introduced a blog post on how to handle auto-translated content and partly translated pages, duplicate to others. Here is a sample of the new code:
<link rel=”alternate” hreflang="a-different-language" href="http://url-of-the-different-language-page" />
Google said, "when rel="alternate" hreflang="x" is included in conjunction with rel="canonical" or 301s, not only will our indexing and linking properties be more accurate, but we can better serve users the URL of their preferred language."
If you have a multi-lingual site, you 100% want to check out the Google post.
JohnMu at Google was very excited about it, he wrote in a Google Webmaster Help thread saying Google has "a neat new technique that can be used on sites that use translated templates for content they make available for users worldwide."
Forum discussion at Google Webmaster Help.