This is good news that Microsoft have fixed this in SharePoint 2010. I seem to recall that this was a problem for a prior deployment with Spanish and English variations.
I was pinged many times for multilingual search in SharePoint in the past. One of the issues is word breaking – in SharePoint 2007 if you set browser language to some other language than you are searching in, you may trigger the wrong wordbreaker and have a bad result. SharePoint 2010 improved on this topic and now it is more multilingual friendly, for example it has Results Query language setting in the webpart. But what is the order of this process? If user set a browser language will it override the setting in the webpart? And do I have to install OS/SharePoint language packs to get my search working?