What is the name and where can I find the manga of Ore-sama Kingdom?
The name of the manga is the same title as the OVA. It is called Oresama Kingdom (オレ様キングダム, Kings of My Love). There is currently no English distributor for the manga nor is there an official English translation of it and the Japanese magazines publishing the series are Chuchu and Ciao.

Source: http://en.wikipedia.org/wiki/Kings_of_My_Love