Rollo, "zinha" in it's literal sense means "little" but it's more of an endearing, affectionate or cute way of calling someone or something. For instance, girls often say to one another "tchauzinho" when saying farewell (literally means "little bye bye").
Brazilian Friend, I spoke to someone from Brazil on Orkut a few months back who knew a lot about Bueno, telling him he should check out this Blast thread sometime..that wasn't you was it?? Anyway, he mentioned to me that recently when Guga and some male pros (as well as Anna K and Martina Hingis) played on a specially-built court/stadium right on Copacabana Beach in Rio de Janiero - Maria Bueno played some points as well and the crowd went wild chanting, "Maria, Maria, Maria." I wish I could've been there!