I've only ever heard it as Seer-ill... like
Cyril Sneer on "The Raccoons". (Now there's a blast from the past) It's not the best association for the name since he was the main bad guy, but aside from that, I'm rather neutral on it.
http://www.youtube.com/watch?v=znOfI-CIMoU&feature=PlayList&p=31186A799A436FCF&index=0&playnext=1