Originally posted by somethinchill
I have a Pentax SMC DA 18-55mm. The wedding will be indoor and out side.
If that is your only lens, then shoot in AV.
The flash should compensate for whatever apeture you choose. Shutter speed will change according to the zoom of the lens per the flash communicating with your camera. It will stay locked below 1/180 sec.
Indoors I would use ISO 400. This will save power to your flash as it will not have to use a lot to get the proper exposure. The K20D has excellent noise suppresion at high ISO's You could probably use ISO 800. I have a K10D and 400 is what I use.
Outdoors you can set your ISO to 100 as there should be plenty of light in the daytime and evening.
As for RAW or JPEG that is your call.
WB should be set to flash.
That is pretty much it for camera settings; that is what I use for weddings.
If you require more info on how to shoot a wedding, I responded to a thread a while back. Let me knoe and I will find it for you.
I just answered your basic camera settings question and I hope this helps.