Symbian Belle is major software update for all Symbian anna devices viz (N8, E7, C7, E6, X7, C6-01, 500) which brings its performance and usability on par with other major OSes like Android, IOS. Check our article for a comparison of Belle with Android.
Nokia confirms on its official twitter account that N8 and other devices are now available in various regions with Symbian Belle firmware pre-installed.
Nokia also confirms shipping Belle pre installed N8 to India as well. Check the second tweet from Nokia,