The Incredible Shrinking Man is a 1957 science fiction film based on a book by Richard Matheson, who also wrote I am Legend.
Guba has it online in 2 parts. part 1:
1000 Misspent Hours says, "the special effects in this film are extraordinary....But most impressive of all is the forced-perspective trickery, which I’m not sure I’ve ever seen equaled." Moria calls this movie "one of the real Golden Age classics" and says it "has a greatness and stature that stands it head and shoulders above (or perhaps considering the theme below) the others" of the "miniature-sized adventure films".
You can watch it from veoh if you're willing to assure them you are over 18 and want to view "mature content". Weird. You also have to download their player, which, after a couple of unpleasant experiences doing so, is a task I'm unwilling to repeat. But ymmv.
11/30/2008:1001 Flicks has a review.
2/1/2009:Only the Cinema has a review.
2/25/2009: Classic-Horror.com says it "is considered one of science fiction's best films".
10/14/2009: Bright Lights After Dark has links on the director's work in celebration of his birthday.