On the Ethical Consumer magazine's boycott list:

Coca-Cola
for its repression of trade union activity in Colombia and its depletion of groundwater resources in India.
...
Websites: Colombia's Food and Drink Workers' Union SinalTrainal, who called the boycott on 22nd July 2003, Killer Coke, and Coke Watch
In India, Coca Cola has caused severe water shortages, polluted groundwater and soil around its bottling plant, distributed its toxic waste as "fertiliser" to local farmers and sold drinks with extremely high levels of pesticides.
Website: India Resource Centre

http://www.ethicalconsumer.org/boycotts/boycotts_list.htm