Some soy cheeses have casein and whey, which are dairy derived. So if you're avoiding all dairy, watch out for those and just eat the vegan cheeses.
That said, the three vegan cheeses I'm aware of are:www.imearthkind.com
(best in my opinion. Melts, tastes great) Comes in Mozarella, caraway jack and nacho cheese.
Galaxy Foods (Soyco) makes Vegan Singles and Vegan Parmesan. It has a more nutty flavor and doesn't melt easily.
Veganrella. I haven't tried it but it's vegan.