What is the difference between an epidural and a spinal?

From e-How.com -

An epidural is adminstered to help with pain relief during labor. It is administered in the epidural space, is slow acting and allows a constant flow of medication.

According to the American Pregnancy Association The needle is inserted and a catheter is inserted through the needle into the back. The catheter is taped to the back and remains in place until after delivery. This allows a consistent flow of pain medication. The epidural will provide pain relief and generally a numb feeling from the waist down.

A spinal is a one time dose of medication administered directly into the spinal fluid prior to a C-section (if there wasn't previously an epidural).

The spinal is administered in much the same way as the epidural with the pregnant woman lying on her side or sitting in a hunched over position. The needle is inserted into the spinal fluid and the pain medication is administered. Unlike the epidural, which involves a constant stream of medication, the spinal is one injection and then the needle is removed from the back. The spinal is more commonly used for short term pain relief.