BEIJING — Microsoft Corp. co-founder Bill Gates and billionaire investor Warren Buffett plan to sell the art of giving to China's super rich in a visit later this month that's already sparked some soul searching among the world's second-largest number of billionaires.Reactions to Gates and Buffett's trip have been swift and varied: One prominent Chinese philanthropist quickly pledged his entire fortune to charity, while the head of a private foundation said Chinese businesses should be leery of emulating American-style charity donations before essential corporate standards such as worker's rights are improved.Read More... More on Philanthropy