From the Asia Times:
Foreign China-watchers tend to see Hu’s anti-corruption efforts in a political light as part of an ongoing power struggle against the legacy of former president Jiang Zemin and his Shanghai Gang, of which the fallen Chen was a member. On the other hand, ordinary people in China see Hu’s housecleaning simply as an effort to make China a better country with the restoration of social justice. In reality, viewing the campaign from both sides provides a more complete picture.
From the power-struggle point of view, it can be concluded that by sacking Chen, Hu has gained the upper hand over the Shanghai Gang backed by Jiang. [Full text]