Migrating Frequent Contacts File in Outlook
Frequent contacts are stored in a file called profilename.nk2
Migrating .NK2 Files XP/Vista/7/03/08
Here are the locations for Outlook 2003/2007 .NK2 files.
Windows XP/Server 2003
C:\Documents and Settings\{username}\Local Settings\Application Data\Microsoft\Outlook
Windows Vista/7/Server 2008
C:\Users\{username}\AppData\Roaming\Microsoft\Outlook
Windows XP/Server 2003
C:\Documents and Settings\{username}\Local Settings\Application Data\Microsoft\Outlook
Windows Vista/7/Server 2008
C:\Users\{username}\AppData\Roaming\Microsoft\Outlook