What is the average salary of incoming staff in the Young
Professionals Program at the World Bank?  Similarly, what is the
typical salary of a professional with equivalent responsibilities at
other large multilateral organizations?

The World Bank does not provide a salary range for the Young
Professionals Program, what they do say on their site
http://wbln0028.worldbank.org/hrs/careers.nsf/key/yp-offer  

under Compensation & Benefits is "Salary: As entry-level professional
in the World Bank, each Young Professional receives an internationally
competitive salary based on their education and professional
experience."

Hope that helps.

Thanks -- I found the same statement when I first tried looking for
salary.  Was wondering if any surveys or publications actually provide
a historical range or average.