Cloth Diapering 101
Cloth diapers of today run the gamut of the most basic to those that almost need a rocket science degree to use, of every imaginable fiber content (cotton, hemp, poly, bamboo even !)
The most "basic" would be
flats - a large single layer of cloth, usually cotton, about the size of a receiving blanket. This is then folded and pinned onto baby. Washing and drying is very fast for these. These need a cover to be waterproof.
The next step would be
prefolds (do not waste your money on the Gerber ones - they're pretty much useless as anything but burp cloths) - these come in various sizes (newborn, regular, premium, toddler) and thicknesses (2x6x2 and 4x8x4 are the most common). Again - folded to fit baby and fastened with either pins or a snappi (a "Y" shaped plastic thing with grips on each end), or is folded and held on with a cover.
After that, there are
prefitted diapers - basically a prefold that has had elastic added at the legs, but still needs something to fasten it on with. These need a cover to be waterproof.
Then
"fitted" diapers. These are about the most common cloth diaper out there, and they vary widely depending on the brand. But the basic configuration is the same - they are shaped, have leg (and sometimes waist) elastic and have a fastening device on them (snaps or velcro). The fiber content is pretty much anything you can imagine - terry, cotton, hemp, bamboo, and more ! Most have an absorbant core sew in, some snap or lay in for faster washing and drying. These need a cover to be waterproof.
Pocket diapers are a cover (waterproof layer) and liner (wicking layer) in one - you have to add something to them for them to be absorbant (called an insert). Fuzzi Bunz is a popular example. The outer layer is typically either PUL (polyurethane laminate) or fleece. The inner layer is typically either fleece or suedecloth. They are shaped, have elastic and fasteners. These do NOT need a cover.
All-In-Ones are basically a fitted diaper with a built-in cover already attached. They don't wash or dry as fast, and tend to have leakage issues compared to using a separate diaper and cover, but are among the most convenient style available.
Covers :
Covers are what you use to provide a moisture proof layer to keep clothing dry.
Pull-on nylon or plastic pants are still available - sometimes from WalMart, Zellers, Target type places even. Easy, cheap, but not the nicest to look at
Wraps are shaped similar to a fitted diaper, but are made of a moisture proof fabric (PUL, nylon, etc) - they have snaps or velcro to hold them on. Also available are wool fabric wraps.
Soakers are knit or crocheted wool covers - they pull on like the nylon pull-on pants do, and often have either ribbing or a drawstring at the waist. Can also be made using old wool sweaters and sewn together with thread.
Shorties / Longies are soakers with legs on them to be worn as shorts or pants.
For the most part, wool used in diapering is softer and creates less of a reaction in people because it has not been treated with so much heavy chemicals like you would find in your typical adult sweater or blanket. Also - you need to lanolize the soaker to maintain it's moisture proofness, and the lanolin (wool oil) keeps the wool much smoother and softer.