I've always stuck by the routine of performing my first oil change at 500 miles for new cars, then going up to 3k-4k miles between all subsequent changes. The reason for the 500 mile change is that new cars need to be broken in. The process of "breaking in" a new engine involves many things like gasket expansion, and the shaving off of imperfections in the crankcase. Anyway, this process CAN produce tiny metal shavings in your oil. These shavings can produce excess wear on the engine during the first 3000 miles. For this reason, I have always changed my new car's oil at 500 miles. I have no manual to back this practice up, but a simple test of pouring your oil over a magnet will give you a good idea of how much wear is actually occuring. It's also a good idea, in my book, to change differential fluid early the first time. Try the magnet test there too...you'll be suprised.