1 Messages from 1 on 1

Click to "Edit Profile" - Preferences
The 3rd choice down that page is "Allow visitor messages on my profile :"

You can choose, Everyone, Just Friends, No one, or Hide the tab.

If you choose "No One" only you will be able to write on it.

If you wish a link to your wall to show at the bottom of your posts
Go To View Your Profile - Contacts - add the url to your Visitor Message/Wall contact.

Please feel free to delete this message