Hey. During my move I happened to find my old campaign notes from the only time I had luck running this setting (I hope with 4e I can try again) and there was a section on religion I had completely forgotten eventhough it's pretty nice touch. I'll share with you.
The main religion which is the polytheistic pantheon (I think I should name this pantheon as a whole. maybe Arandonian Pantheon).
So anyway the religion consentrates more on the whole pantheon than on the individual gods. The laymen worship all the deities equally so for normal classes choosing a deity is forgone, unless they choose different faith altogether. Also most priests are priests of the whole pantheon but here there are few exceptions (I'll address that later). There are also no multitude of temples dedicated to different deities but instead there is only one temple in each city, which is dedicated for the whole pantheon. It depends on the time of the year and specific occasion, to which deity the rites are dedicated on any given time.
The assosiation of priests: The female priestesses of the faith are assosiated with Skaia and the male priests are associated with Aur, eventhough they are always adversaries of the whole faith. Also since the lesser portfolios of Skaia and Aur include winter and summer the rituals are performed by priestesses from mid-autumn to mid spring and priests during the summer half of year. On equinox's there is grand celebration which culminates in a ritual combat between High-priestess and High-priest. The combat ends in the victory of the priestess on autumn-equinox and of the priest on spring-equinox, and marks the change of the temple calendar.
There are few exceptions. A priest can choose to dedicate his/her service to a specific lesser deity and take care of a shrine of said deity. Most deities have small shrines scattered across the land. These are usually situated on some holy sites and consists of little more than an altar and a cabin nearby where the caretaker lives. The shrines are locations of pilgrimages and most deities don't have more than a few in the whole world.
The Grand Temples: The three major deities have also grand temples which are the center of worship of these deities (Actually they are for the three what the shrines are for the lesser deities.)
Skaia's Grand Temple, The Crystal Palace of Lake-End is a magnificant palace made of purest crystals. Skaia also has an oracle who resides here. She is considered the physical manifestation of the goddess of love and it is true her power is great. (One of the few true clerics of the world)
Aur's Grand Temple, The Sunhall is nothing more than a ring of columns on an island on Shrin. Here some mystical force keeps the weather always clear and the priests manning this temple live on the bare ground.
The Warrior's Grand temple is on a mountaintop near Doringdel. It is forbidding place and the way there is filled with danger. The temple itself is a great arena where the greatest warriors across the lands come to test their mettle against eachother and the priests of Warrior.
OK. That was quite long, hope you got the idea and like it.