After a preposition the objective form of a pronoun . . . must always be used: believe in him; between us; for them. This is especially important when two pronouns are linked by and or or: between you and me (not I); a gift from my brother and me (not I); I asked if there was any chance of him (not he) and Gina reconciling. New Fowler, p. 617.
Many people make the mistake of using the subjective case (I, we, he, she, etc.) instead of the objective case (me, us, him, her, etc.). The mistake usually arises when the preposition has two personal pronouns as objects. Note the mistake in the title of my book: A Grammar Book for You and I, Oops, Me! The preposition for requires objective pronouns to follow it. Thus, me, not I. So watch out for the following: