“Between you and I” is a grammatical error that occurs more often in speech than in writing. It is no less grating, though, to hear that phrase and its variations than to read them. (I came across a direct quote with this construction recently and groaned loud enough for my cubicle mates to hear.)
“Between” is a preposition, and the pronouns are its objects. We need the objective case of the pronoun here: me, him, her, us and them.
This article was originally posted by the Raleigh News & Observer, a subsidiary of The McClatchy Co.; is posted here to provide continuity; and is copyright © 2011 The News & Observer Publishing Company, which reserves the right to remove this post.