For the U.S. members:
I just ordered 8 quarts of Castrol TWS 10w60 oil from Tischer BMW,
www.getbmwparts.com for $9.75/quart. That is an excellent price!
I purchased 1 quart from my local BMW dealership last week for almost $23.00! Also, they wouldn't fill the car with oil for free as some have mentioned. I got into a huge argument with the service manager about this.