Interesting in that the Huffington Post addressed this like this morning.
http://www.huffingtonpost.com/2010/0..._n_672393.html
saying
At a high-end restaurant where the sommelier has played an important role in the wine program, it's appropriate to give 10-15% of the price of the wine directly to the sommelier. However, when paying the bill, diners should deduct the price of the wine to calculate the tip to go to the waiter. At most meals, it's okay to just tip 15-20% of the final bill and let the restaurant divvy it up.