In fact I'm thinking about good liches, and have found one in 'Complete Guide to Liches':
...Should the saving throw succeed, though, a startling transformation occurs - flesh and blood begin to re-form around the lich's body. The lich, while not exactly living, has purged itself of all the necromantic energy that kept it in its state of lichdom, and is reborn instead with positive energy to keep its centuries-old form in existence. The redeemed lich looks exactly the way it did the moment before its lips sipped the potion of undead life, and will look that way until finally destroyed.
A redeemed lich retains many of the properties that it possessed in its more evil form. These powers and abilities, though, are changed slightly. The redeemed lich retains its fear aura, but this fear is only effective against creatures of evil. Neutral creatures are completely unaffected by the aura, and for creatures of good the fear aura now acts as a bless aura, as the spell of the same name. The redeemed lich's paralyzing touch only works against evil beings, and its touch attack dealing negative energy to foes becomes a healing touch that restores the hit points it once took away. Apart from that, its abilities remain the same as they were when the lich was a vile being of evil.
In short, 3 changes if a lich turns to good:
1 Returns to living form and becomes immortal
2 Fear Aura only affects evil creatures, and to good ones it's a bless aura
3 Touch Attack only paralyzes evil beings, and has healing effect
So is it possible to add this 'Ex' lich -- when a lich turns to good things change in this way? Although this is said to happen 'on the rarest of rare occasions', but I think Redeemed Lich will appear all over the world if PRC makes it
Just for fun, since a new aura & touch attack aren't easy to be implemented. Still suggest 1st -- the skeleton apperance seems too ugly...