The car's computer has a build in maintance minder. The computer will determine when you need any type of service. It will display a code, for example: Maintance Minder A. Then look in the back of the owners manual and it will tell you what services need to be performed according to the code. The first oil change isn't needed until 10,000 but the computer may tell you sooner or later. Some people on here have changed sooner or later then what the minder says. There is a whole thread on 'Oil Life', check that out.
http://www.greenhybrid.com/discuss/oil-life.5109.html