A. The normal method for checking which local groups a user belongs to on a machine would be to start User Manager and double click on the user in question and click the Groups button.
If however you wanted to see which local groups on a server a member of another domain belonged to there is no way to do this. Fortunately a utility from http://www.fidutec.com has been released as FreeWare which does exactly this. The diagram below best illustrates how it works.
Download from http://www.ntfaq.com/download/gestgrp.exe