Kenyatta,

About ZIM economical involvement in DRC do some research about Mr Billy Rautenbach:

"For reasons of alliance and payment of the war bill estimated at US $45 million, Kabila had signed an agreement between the "GECAMINES" and the Zimbabwean company Ridgepointe Overseas Developments of British Virgin Islands, which belongs to the RAUTENBACH family. The latter has good relations with President Mugabe, who, in turn, feels very close to the rich cobalt reserves of Katanga. This guarantees and helps to justify the presence of the Zimbabwean military in DRC, next to Kabila.

Billy RAUTENBAUCH, who is the Director of this Zimbabwean group, Ridgepointe, is currently leading the GECAMINES recovery committee. This confirms the fierce involvement of Zimbabwe in the resistance put up by DRC in the war led against the Ugandans, Rwandese and Burundians and their Congolese collaborators." in http://www.geocities.com/zcliste/mine2.htm.
He is still active.

Another link is the "Osleg" company: a ZAF operated company that was very active in DRC.

Finally, "A detachment of the Zimbabwean Presidential Guard is now providing close security for the youthful Democratic Republic of Congo (DRC) President, Joseph Kabila. It is not known why General Kabila has decided to put his life into the hands of the Zimbabwean National Army (ZNA) rather than those of Congolese nationals." in http://www.afrika.no/Detailed/10159.html

Hope it will help.