The definitive word from Matt Cutts in a 9 Minute video on cloaking. There is no white hat cloaking. I had issues with this recently on a site when implementing a mobile redirect. I had redirected users but not the googlebot mobile user agent. After hours in webmaster help and some coding changes we fixed this issue. As the video states redirecting mobiles is fine as long as the mobile version of google gets the same treatment. The same with some language versions of the site where there is a legitimate reason to redirect users, but you should make sure Google is getting the same treatment when it crawls your site. Its always nice to get a proper definitive video from Google themselves on some tricky topics.
There is no white hat cloaking – Matt Cutts
November 4, 2011