This assembly is used to get language specific resources for an application. These language-specific assemblies work in side-by-side execution because the application has a separate product ID for each language and installs satellite assemblies in a language-specific subdirectory for each language.
Links- http://www.dotnetspider.com/qa/Question16767.aspx
http://www.codeproject.com/KB/aspnet/SatelliteAssemblies.aspx
http://msdn2.microsoft.com/en-us/library/21a15yht(VS.71).aspx