Factotum

Some facts: 
official chinese statistics for sufferers of HIV and AIDS put the figure at slightly less than 1 million people, however the chinese authorities' strict restrictions on free journalism and their crack-down of human-rights activists could mean that figure is much higher: http://en.wikipedia.org/wiki/HIV/AIDS_in_China#Activism ;
China's bid to present a harmonious and peaceful China during the Olympics has led to the arrest of many "activists" including blogger Hu jia, jailed for "inciting subversion of state power" - a good translation of that phrase would be "speeking freely about environmental, religious and health issues":  http://news.bbc.co.uk/2/hi/asia-pacific/7327763.stm ;
China continues to send back North Korean political and economic refugees who face extremely harsh repression upon their return to North Korea, even though China is obliged not to send home any refugee who may face reprisals upon their return as stated in the 1951 United Nations Convention on the Status of Refugees and its 1967 Protocol:  http://www.rfa.org/english/news/2005/02/25/us_nkorea/ ;
the Chinese government continues to encourage ethnic Chinese to "migrate" to Tibetan areas, thus diluting the Tibetan culture and Tibetan control over the area: http://news.bbc.co.uk/2/hi/south_asia/7302661.stm ;
Corrupt Communist Party officials have often favoured developers wishes to 'forcibly evict' tennants from their homes, with money the major power over peole's rights:   http://www.hrw.org/campaigns/china/beijing08/evictions.htm ;
With no laws to protect animals in China there has been wide-spread murder and torture of various animals including dogs and cats, as well as taunting and abuse of zoo animals. Europe and north America have banned Chinese fur imports as some statistics researched by the Humane Society of the US suggest as many as 2 million cats and dogs were murdered for their skins alone: http://www.buyhard.fsnet.co.uk/animalcruelty.htm ; http://www.heathermills.org/campaign_dogcatfur.php ;
China has (some reports suggest) over 900 missiles aimed at Taiwan. China considers Taiwan to be a part of China, just like Tibet. Taiwan has a free and democratic society, which obviously would not fit into the Chinese model of society, where people are told what to do and if they don't do it they could go to jail. Or just disappear. ANyway, I digress. United Nations Resolution 1514, also known as 'The Declaration on the Granting of Independence to Colonial Countries and Peoples' staes:  "The subjection of peoples to alien subjugation, domination and exploitation constitutes a denial of fundamental human rights, is contrary to the Charter of the United Nations and is an impediment to the promotion of world peace and co-operation" and " All armed action or repressive measures of all kinds directed against dependent peoples shall cease in order to enable them to exercise peacefully and freely their right to complete independence, and the integrity of their national territory shall be respected":  http://en.wikisource.org/wiki/UN_General_Assembly_Resolution_1514 ;
Just take a browse down through the Universal Declaration of Human Rights signed by all members of the United Nations General Assembly, including China. Do these universal rights apply to China too???: http://en.wikipedia.org/wiki/Universal_Declaration_of_Human_Rights#Overview_over_the_rights 

These are just a few reasons that people should boycott the Beijing Olympics. If Governments of the world are too money obsessed to brush aside issues of freedom and humanity then it's down to the people of the world to try and change their minds.