http://www.washingtontimes.com/apps/pbcs.dll/article?AID=/20080221/NATION/793341537/
Sorry, it's a massively long URL! But worth the effort, I think.
My query of the day is, how and when did the extra L invade the respectable and indeed Latin name of Hilary? Is it an American speciality, er, specialty? I've never encountered it in South Africa, or in the UK, and I can't think of any analogous names that might have influenced the spelling.
All the best