Here is the best write up (link is below) with pics for a997 oil change i have seen. Over all it is very easy to do. I did it my self too when i picked up my P car at 8K. Good luck
There is no offical "15K service" The manual says 20K: minor service and 40K Major service. Most people have been recommending oil change at 10K (or sooner for 1st oil change) or once/year. Hope this helps.
Click on this link:
http://forums.rennlist.com/rennforums/showthread.php?t=286484&highlight=997+oil+change