Outlook Contact SharingResource:
http://infotech.wsu.edu/connectsupport/HowTo/SharingInfoInOutlook.html
To share this folder you need to do two things:
Set the 'Folder Visible' permission for the person(s) you want to grant
access to this folder to at the root level of your Mailbox Account.
Set the permission level for the specific folder you want to share for the
people you wish to grant access to.
To set the permissions on the root level for your account, navigate to
your mailbox on the server and right-click on it:
Select Sharing, then add the account you want to share information with,
but just set the permissions to 'Folder Visible'
Now find the specific folder you want to share, right-click on it then
select 'Sharing'.
Now add the person you want to share this folder with and set the
permissions as you desire.
Now for other people to see these folders, have them go to
Tools, E-Mail Accounts, View or change existing e-mail accounts
Select the Exchange account, click 'Change'
Click on the More Settings Button
Click on the Advanced Tab
Now you can Add the accounts whose mailboxes you wish to open in Outlook.
Click on Add and specify the account name of the person who has shared
their folders with you.