is there a Web page to convert English spellings?

Since English is a global language and doesn't have very consistent orthography to begin with, a number of different systems of spellings have developed. The most famous have to be the differences between American and British (or Commonwealth) English. I found this useful list of the differences on wikipedia some time ago, and have always been amused by the Economist's list of Americanisms. But today it occurred to me that if there are Web pages that convert one language to another (sort of), there ought to be a site that does the same for American and British spellings.

I couldn't find one, tho there are a number of downloadable programs that claim to be able to do this. I had trouble getting most of them to work, and as a Mac person most of them are not useful to me anyway. If anyone knows of a site that does this, tho, I'd like to know.

It turns out that this might be rather difficult, tho probably less difficult that the problems facing BabelFish and similar translators. One programmer wrote of some of the difficulties here.