Need to set up Lion Server first, then:
Copy the wiki data located in /Library/Collaboration/ by default or in the location specified in Server Admin on the v10.5.8 or later server to a local volume Lion Server can access.
Use the following steps to manually migrate your Mac OS X v10.5.8 or later server’s Wiki data to Lion Server.
If you are migrating a v10.5.8 wiki server’s data, make sure Lion Server is bound to the same Open Directory master as the v10.5.8 server, so the ACLs for wikis can convert. If not, wikis are only readable or writeable by admins, and ACLs must be reset.
To migrate wiki data:
1 Start Wiki service in the Server app.
2 Enter the following command.
sudo wikiadmin migrate -r /path/to/collaboration/folder