I just ran across this article on Consumerist about the 3000 mile oil change. Basically, it's completely unnecessary for most people, particularly those who drive newer cars.
Now, I usually split the difference between what the owner's manual says and what the oil change guy says. But that's still too often nowadays, and it appears that the people who wrote your operator's manual were right all along. Don't believe me, or Consumerist, or the manufacturer of your particular vehicle? Believe the State of California, who have apparently done some research on the subject:
So changing your oil at 3000 miles is a waste of money, doesn't help your car, and is bad for the environment. Who knew? Sorry about this being short; I know how certain people frown upon this, but I thought this was something worth sharing, even if I don't have 10,000 words to write about it.