I disagree a bit. I agree that it is not a publication, and few things blows a person's credibility quicker than presenting themself as an author when they are not. However, I think you definately should let admission committees know that you are actively involved in research work. How that is presented depends on what you did.
I had a boss (for only two weeks fortunately) who claimed he had over 300 publications. But 295 were bookreviews for a lay-reader's online magazine. Yes, I think he was a fraud.