You're mostly right, pedant. However, as the immigrant population in the USchanges, there are more and more people here who were educated to use British english and one sees it occasionally.
Now that SOMEONE
![Wink [;)]](/emoticons/emotion-5.gif)
has finally replied to this thread, I can show off a bit of arcana :p
While and whilst are more or less interchangeable when the meaning is although or whereas. For example: Whilst many people agree that SUVs are hazardous on the roads, little or no effort has been made to limit their use. One could easily substitute "Although..." or "Whereas..." for Whilst and the meaning would be the same.
However, whilst also means "when" and is considered more formal and probably even archaic. I do see it in older (including 20th c.) novels, though, and I think this meaning should be known and understood by english speakers. For example: I saw him while I was waiting for a train. OR I saw him whilst I was waiting for a train.