Certainly. In fact, most of the cakes I grew up learning how to make (in the UK) call for self-rising flour (the exception being rich fruit cakes). It's much more common in home baked goods there than AP flour.

Another thing to remember - make sure you sift, or fluff your flour before measuring - especially if you are making your own self rising flour. It's a common mistake to just stick a measuring cup in the bag and pull out a scoop. However, most recipes are created with aerated flour in mind. So if you are making your own self rising flour, the ratio of baking powder to flour will be off if you don't sift (best) or fluff (better) your flour.

Of course. You just need to consider that a cup of flour has about 1 teaspoon of baking powder, and adjust your recipe.