Well, there's obviously the SRD to consult (I like
www.d20srd.org for the hyperlinking), but here's a quick rundown of the ability:
Luhal can change to any (Medium) or (Small) creature with the (Animal) subtype with no more HD than he has, as a standard action. This does not provoke an attack of opportunity. He can shift to an (Animal) twice a day. Any time he is in wildshape, he can shift back to human (another standard action, no AoO), but that ends that usage of the ability, as does shifting to another animal. If he doesn't end it early, it lasts a total of 6 hours before he shifts back to human form.
Whenever he wildshapes - to invoke or to end - he is healed as if he'd had a full night's sleep. (1 hp per level)
Anything he wears or carries melds into the new form, but any powers thereof normally cannot be invoked while they are melded. (Items carried in non-human form fall to his feet when he shifts.)
Normally, you have to be able to use human speach and gestures to cast spells in wildshaped form, but Luhal has a Feat that allows him to cast as long as he can move his limbs and make noise.
He keeps his hit points exactly as they were, but otherwise adopts the average physical stats of the animal. (This may affect his Ref save) He keeps his skill ranks, feats, base attack bonus, and base save bonuses.
He gains the natural weapons, natural armor, movement modes, and extraordinary abilities of his new form, but loses the ones of the old.
Each level he gains, the maximum duration of each wildshaping is increased by an hour. At 7th, 10th, 14th, and 18th levels he'll get another wildshaping usage. At 8th level, he can wildshape into large animals, Tiny at 11th, and Huge at 15th.
At 12th level, he can start wildshaping into (Plant) creatures.
At 16th level he gains a parallel ability to wildshape into Elementals.
-Albert