Actually, since it's a latin word (for "Arts", as in the "art of magic", as opposed to a skill, because the concepts of art and skill had very specific meanings to Romans, which they inherited from the Ancient Greeks), I believe you are supposed to pronounce it like "Arrrss" (Think, like a slurry drunken pirate), with a downward tilt to the sound at the end, almost like an unspoken "uh" sound. The European-English slang word for people's backsides has an upward tilt at the end, because of the barely pronounced "e" (ars-e, one extra letter does happen to change the sound a little). Admittedly it's a small difference, but since I've spent so much time studying this stuff, I might as well use it, ya know?
amusingly enough (since I believe this is an international board) there are plenty of Americans who have no idea what "arse" is at all, they've never heard of the word. I've noticed most forum dwellers are more widely read.
