This article is from the Food Preserving FAQ, by Eric Decker email@example.com with numerous contributions by others.
The most specialized piece of equipment that you'll need is a crock,
which is just a large, non-reactive, smooth container. You need a big
container, because you might as well do a lot of pickles rather than
just a few; you need a non-reactive one (see below) because you will
be working with salts and vinegar, and you don't want metals in your
pickles. You also want a smooth container, because a lot of microbial
spoilers will cling to rough edges, making it hard to clean
Other things you'll need: waterbath canner, canning jars and lids,
timer, wooden spoons, heavy plates, cheesecloth. One of the most
important things for successful pickles is a cool place. The crock
shouldn't get above 70 F, otherwise the pickle bacteria/yeast grow too
quickly and spoil the pickles.