Ghost Hunter
Prerequisites: Perception 1 rank
Benefit: When attacking an incorporeal creature you may make a DC 15 + the creature’s hit dice perception check as a free action, if you succeed you can harm the creature with non-magical weapons (which do half damage) or if wielding a magical weapon a successful check allows you to do full damage.  This check must be made for each attack including multiple attacks from the same weapon.  If the target’s incorporeal nature is the result of a spell the DC is instead 15 + plus the caster level + the spell level.
Normal: You do no damage with non-magical weapons and half damage from magical weapons to incorporeal creatures.

Ghost Armor
Prerequisites: Ghost Hunter, Perception 5 ranks
Benefit: When being attacked by an incorporeal creature you may make a DC 15 + the creature’s hit dice perception check as a free action, if you succeed you can apply half your armor, shield, and natural bonus (rounded down) to attacks made by an incorporeal creature.  This check must be made for each attack.  If you have 10 or more ranks in Perception you apply your full armor bonus for armor, shield, and natural armor on a successful check.  If the attacker’s incorporeal nature is the result of a spell the DC is instead 15 + plus the caster level + the spell level.
Normal: You do not gain your armor, shield, or natural armor bonus against attacks from incorporeal creatures.

Ghost Grappler
Prerequisites: Ghost Hunter, Improved Grapple
Benefit: You may make a DC 15 + the creature’s hit dice perception check as a free action in order to try and grapple an incorporeal creature.  You must still make a grapple check as normal.  You must continue to succeed at the perception check each round of the grapple.  If the target’s incorporeal nature is the result of a spell the DC is instead 15 + plus the caster level + the spell level.
Normal: You cannot grapple incorporeal creatures.