Like the operating system options on your computer, there are really just a few big players in the mobile operating system market. Android and Apple's iOS take up the lion's share, followed by the Windows phone operating system and the one Blackberry uses. So is there room for one more? We're about to find out. Firefox, the popular open source web browser owned by Mozilla, is getting ready to launch its own operating system for smartphones. Mozilla plans to offer Firefox OS starting in July. But not in Western Europe, the U.S., or China. Instead the company will focus on countries in Latin America and Eastern Europe. Less competition, maybe. But also, more potential customers.