As an aside to your edit, I have also seen "different than" used more and more often of late. I'm not sure if it is an Americanism that I was just unaware of. It's not that "different than" is wrong, it's just different from what I'm used to!
In Year Eight at school, I had an English teacher who liked to mix things up a little. One time, I was answering a question in class, and I used "different to" or "different from" or something -- maybe even "different than", I don't remember now. The teacher told me to stand up, then explained that there was a right form and a wrong form for this, and got everyone to pick sides -- "than" here, "from" there and "to" over there. Then I bamboozled him, because I noticed that the smartest girl in the class, a gorgeous lass who gloried in the surname of Snodgrass, had picked a different side, so I reasoned that she was more likely right and defected to the same group. The teacher was deeply annoyed that I apparently didn't have the courage of my convictions; my point, which I understood instinctively even at that age, was that embarrassing a student to make a point was a totally shit way to educate people, and if he was going to place such a high premium on game playing in class, he could call me Kobayashi Maru.
To this day, I still can't remember which is correct - "than", "from" or "to". But I can remember the look on his face, and the fact that after that he stuck with slightly less aggravating teaching methods.
I believe that "different from" is most common across all dialects of English: http://alt-usage-english.org/excerpts/fxdiffer.html (Note: This only compares UK English and American English, not "all dialects".)
