As researching new technology today on the web (as always :^), I came across this site that have origins of many Chinese surnames - all the way beyong the Zhou dynasty! So I went and found my surname "Yang" listed in their site. Here is the entry -
The 6th most common last name in China. Yangs are the descendents of the Xi Zhou Dynasty. The third son of Zhou Wu Wang, Tang Shu Yu was awarded the land of Jin. His descent Jin Wu Gong was awarded the Yang city (Hong Dong of Shanxi Province) and bore the last name of Yang and Yang She (Goat Tongue). Around 514 B.C., a rebellion took place, both the Yangs and the Yang She's were persecuted. They migrated south to Hong Nong Hua Yin. About 90% of famous Yangs in the history came from Hong Nong Hua Yin.
Gee. I am really impressed. I barely remember these historical names from my junior high school history classes in Taiwan, but now I know the roots.