Associated Press: Shares of several major oil companies and those that provide related services fell Friday as a massive oil spill cast a pall over the drilling business in the Gulf of Mexico. Oil spewing from a deepwater well operated by BP PLC has reached Louisiana’s wetlands. The White House put a hold on new offshore oil projects until the rig disaster that caused the spill is explained. As the extent of the spill unfolded, investors sold off stocks of many companies that operate in the …