If you don't live in Austria, Europe, you've most likely never eaten a "real" Wiener Schnitzel, so forget everything you know about it.
This delicate Austrian speciality, is often copied, but nowhere outside of Austria have I ever eaten anything that resembles the original.
The original Wiener Schnitzel is made from veal, although you often find it with pork, but this has to be called "Wiener Schnitzel vom Schwein" on the menu, otherwise the restaurant is trying to trick you.

You need the following ingredients for a real Wiener Schnitzel:

veal escalope (alternatively pork or chicken)
flour (the right type, called "griffig" in german)
2-3 eggs
bread crumbs (from white bread buns, but not the soft McDonalds type)
lard and a pan

Follow these steps:
Using a meat hammer, flatten the meat. Cut off all pieces of fat that might be visible on the edge.
Using a knife, make little cuts into the edges of the meat, this prevents that the meat will roll up when fried in the pan.
Use a little salt and pepper to season the meat.
Drop the meat into a bowl filled with flour, and press until the meat is fully covered with flour on both sides.
Open the eggs, and drop their contents into a shallow bowl. Use a fork or something similiar to stir the eggs, then drag the flour-ed meat through the bowl, until it's fully covered with egg on both sides.
Finally drop the flour-ed and egg-ed meat into a bowl with the bread crumbs, until the meat is fully covered with bread crumbs on both sides. Put the lard into the pan, and heat it. It should be half as high as the meat. When it's hot enough, fry the meat in the pan. Be sure the reduce to temperate, otherwise the Schnitzel will be dark and burned on the outside, while still raw on the inside. This part requires a little practice (or should I rather say: trial and error?), and also depends on your oven. The general rule of thumb is to keep the temperate lower than expected, which will take longer, but prevent burning the Schnitzel.
If you get it right, the ideal time to take the Schnitzel out of the pan, is when it's golden-brown.(on both sides, so you have to flip it once)

A real Wiener Schnitzel is best served with potato salad, fried potatoes, french fries or rice.