Every school I've interviewed at so far (and those that I have yet to interview for) had an essay as part of the interview process. I don't know if it's something every pharm school requires, but it certainly seems to be so for the vast majority (in California at least).....don't worry though; they are short and easy -- the admissions people just want to make sure you can string together a proper sentence, so it's all about grammar and language, NOT content (so no need to study for anything).