The normal D&D alignment system is gone. However, alignment based spells are still around - its just that the effects vary based on your patron deity. Detect Evil, for example, will detect enemies of your deity, and followers thereof. Detect Good will detect followers of your deity or any allied deities - though it is typically not used at all. If you don't have a patron deity, and cast detect evil, you won't get any results at all - but likewise will not (generally) detect as being evil.
Blasphemy, Dictum, Holy Word, Word of Chaos - all leave unaffected any followers of your deity and of any allied deities. Use the effect listing for Dictum to determine the spell's effect.
Chaos Hammer, Holy Smite, Order's Wrath, Unholy Blight - use the listing for Order's Wrath to determine the effect.
Cloak of Chaos, Holy Aura, Shield of Law, Unholy Aura - use the listing for Holy Aura; the blinding effect lasts until the end of the attackers next turn.
The plane of shadows is replaced with the plane of dreams. It still serves the same functions of powering some illusion spells, and acting something like the near umbra in world of darkness - a twisted reflection of the normal world as it would be seen in the dreams of those who live (or lived...) there.
Death & Resurrection:
The gentle repose spell has one additional effect: if cast within one hour of death, it anchors the soul to the body, preventing it from moving on to whatever afterlife it was headed for. This binding is very weak, however, and anything else that affects souls will override it - i.e. soul bind, true resurrection, true reincarnate, clone, or even a mere raise dead (if preceded by miracle or wish to create a viable alternate corpse). It is also completely sundered by any form of planar travel. While in some situations this can be a good thing, it is also a necessary measure for any of the more powerful undead creation effects - as, without the soul of the deceased being present, only non-sentient forms of undead are possible.
Any divine spellcaster can raise those who follow the same patron deity at one-fifth the normal cost. This cost reduction also applies to create undead spells that create sentient undead.
When an individual who does not follow a specific deity dies, their soul is collected by the celestials, who judge it. If it is found worthy, it is reforged into a celestial. If not, they hand it over to Coyote, in hopes that it will fare better the next time around. The celestials who do the actual judging, however, are overworked and underpaid, resulting in a current waiting time of almost three hundred years - good news to anyone planning to get a comrade raised.