Reports from both the LA Times and The Wall Street Journal indicate that Apple is currently in talks with movie studios to store and possibly stream movies through iCloud as early as late this year.
From WSJ:
Apple Inc. is negotiating with Hollywood studios for deals that would let people who buy movies from the iTunes Store watch streaming versions of those movies on Apple devices such as iPads or iPhones without manually transferring them, according to people familiar with the matter.
Rumors have surfaced in the past that Apple was working with movie studios and may be preparing a streaming service (possibly called iTunes Replay), and this duo of reports from large media establishments adds some new credibility to those reports.