"Different than"?

"Different from" is usually correct. "Different than" is probably more commonly used but most often wrong. Someone might say, "Soccer is different than football." Wrong. "Soccer is different from football." (But only in North America and a few other places. In most of the world what we call soccer is called football.)

"Different than" is only appropriate when followed by a clause, such as: "The rules of football are different than they used to be." But, saying it a different way could change "than" back to "from": "Football rules today are different from the rules of the past."

Basically, if from sounds OK, it's usually the right word to use.