In my limited experience, they should be okay together, as long as the Oscar is not big enough to eat the African Cichlids of course! They should be okay I think.
What do you mean by African Cichlids? You see I live in South Africa and here we call them Malawi Cichlids because they come from Lake Malawi. I think that is what you are referring to. Nice brightly coloured fish? Blues, yellows, oranges, nice leopard-spots etc etc.
I like them very much! I also want to get some but I know they will get too big for my tank and then I will have to sell them and I don't want to do that!