When foreigners come to China and go online, they immediately found that they lost access to twitter, facebook and a lot other connections they use on day to day basis. Some have the knowledge and resources to have a VPN setup before leaving their home country. But others are out of luck.
I posted a step by step guide for using GoAgent, a self proxying program. http://memallery.web1337.net/how-to-use-goagent/
Please check out and enjoy!