After upgrade the Nokia Maps to version 3.09 along with the update of Nokia Belle Refresh on my N8, 'Check In' feature is no longer available to use. It is just only available in China.
I don't why Nokia want to disable it to be use in other countries. I just seldom use it because I'm using Foursquare often to check in.
Source: Nokia FAQ
Nokia Maps Suite 2.0 and Maps 3.09 install the Check in application only in China. In the other regions Check in is not installed as part of the Nokia Maps Suite 2.0 bundle.