A Lich Wizard can summon a Lich Shade as a servant, when summoned it can remain undead for up to (caster level divided by 4) hours/day. The Lich Shade does not count as a familiar.
This ability alters arcane bond and scribe scroll.
A Lich Wizard can't choose Necromancy as his opposition school. Further more all his saves and dc regarding the Necromancy school increase by 1 every 6 levels, starting at 3rd.