just thought i'd bring things up to speed instead of making a new thread about the movie:
It's called "Stewie: The Untold Story, and it'll be out on DVD on September 27th. The Hollywood Reporter states, "The movie finds Stewie, the maniacal baby genius, having a near-death experience that prompts him to change his ways. Instead of seeking to dominate the world, he sets out on a road trip to find his real father." Giddy up.
^ full yahoo news story about it.