-If you are going to federate to MSN/Live are any users using a msn address that is the same as your Lync address will be? If so they must change their MSN/Live ID. Here is how.
-Do you have the certificates you need?
-Is your Active Directory Forest functional level 2003 or higher? (has to be Native mode)
-Install Exchange 2010 UM role
-Give Lync implementor AD user part of the "Organization Management" group
-If server2003 make sure server media accessible
-company City, State, Zip
Things to do when done:
-add user who wants to administrator CSAdministrator group.
-document DNS A records
-document SRV records