What preparation is done to banana peppers?
Most Comercial banana peppers are indeed pickled. This is relatively easy to do yourself or you can eat them fresh. 

Eaten fresh their taste varies depending on the capsaicin present but the vary from a bell pepper flavor to a flavor similar to a jalapeno. The amount of capsaicin varies widely between cultivars so ask your plant/seed vendor to inform you of the variables that affect heat (alternatively you can ask on gardening and we'll do our best to help you grow them). 

If you prefer the pickled flavor but want to make them yourself canning them is pretty trivial (I've done it, so it has to be pretty easy). I used a hot water bath canning method that involved a weak vinegar solution and some garlic following normal hot water canning procedures (I can't dig up the exact recipe at the moment, but any canned pepper recipe should do). I had enough for about a dozen pint size jars so I needed to put them up, if you only have enough to last you a few weeks it would be worth looking into a refrigerator pickle recipe as mentioned in the comments (or freezing and pickling as you want to eat them, although I'm unsure of the results this would give).