Parasites are the most popular way to get a good hard working, flesh eating zombie, but as of yet there haven't been many parasites that can do this, to humans any way. The glyptapanteles a parasitoid from wasp larvae is injected into a host caterpillar, not to uncommon right?

Well after the parasite eggs hatch the wasp larvae eat their way out from the inside of the caterpillar, still not to uncommon. However, the strangest part is that instead of dying like a normal half eaten caterpillar, this one actually watches over the wasp larvae and even raps them in silk, like a loving mother coddling her young.

Now there are many other parasites that will do similar brain-control-type-maneuvers to either get their host killed or to have their host protect something that they shouldn't be protecting, like in the glyptapanteles case the wasp larvae. That is just nature's way of creating a great zombie, however it is much more likely that humans will create zombies before parasites adapt.

From nano-bots to bio-warfare there are a number of ways people could create zombies. Slightly altering diseases like mad cow (or when it is in humans, Creuztfeldt-Jakob disease) would be an easy way
to make a zombie-ish disease that could spread rapidly throughout every major city around the globe.

Look at the symptoms: changes in gait (meaning you are walking weird), hallucinations, lack of coordination, muscle twitching, delirium and dementia. These are all classic zombie give-a-ways, during a zombie apocalypse if you see someone stumbling up seemingly delirious and probably hungering for human flesh, you should probably flee.

You are going to need to be able to be self-sufficient during the apocalypse, this means that you will have gardening supplies for after the dust from the major onslaught has cleared. During the blitzkrieg you should probably have a good warehouse you can camp out in until it is all settled.

A place with drinkable water, food storage, and hopefully some sort of range or something, this would make a good warehouse, bomb shelter. Now as far as zombie apocalypse actually happening, it is hard to say, perhaps it won't.

But if it isn't a zombie apocalypse some other gigantic catastrophe is going to level the earth sooner or later, so it is going to be good to be prepared either way. Start collecting food, water, and probably guns and ammunition.

Who knows what the future holds in store. It is best to just be prepared.