http://www.factmonster.com/country/profiles/congo-(kinshasa).html...

http://www.factmonster.com/country/profiles/congo-(kinshasa).html#econ
Is a good overview.

http://www.pri-center.com/country/country_specific.cfm?pgid=2&countrynum=215
Good site for political risk – has many links worth reading especially
“DR Congo Reviews 60 mining deals” BBC news June 11th,
and “OPIC Approves Up To $400 million in Financing and Imsurance for Copper Project in DR Congo”

http://www.fraserinstitute.ca/
Search “Congo” turns up some really good research fodder.

There are many other worthwhile sites for researching the sovereign risk in the Congo .. but these may give you a good starting point. Happy researching !!