Recently I received some questions about the IE language setting that affects the MOSS search results. It seems the MOSS (like ASP.NET 2.0 application) has taken advantage of the CultureInfo class to directly convert the client browser's user-language setting( [lang]-[region] such as en-us, zh-cn) to a CultureInfo instance. Sammy Jankis has provided a blog entry explaining on this:

#How To: Avoid IE language settings affecting MOSS search results
http://blogs.microsoft.co.il/blogs/adir_ron/archive/2007/12/11/how-to-avoid-ie-language-settings-affecting-moss-search-results.aspx