It's pretty simple, but it takes a very, very long time. However, you'll find that the various extracts provide a unique and delicious flavor.

1 vanilla bean of the "fine vanilla" grade
3/4 cup of hard alcohol - vodka, rum, brandy, or bourbon

Split the bean lengthwise and put it in a bottle tall enough to hold the bean. You might have to snip the bean to make it fit the bottle, just put the snippings in. Pour in the alcohol and cork the bottle. Leave it to steep for six months.