a relatively dumb question i'm sure...

hi,

i've been trying to do more with woodworking than simple home repairs
and i've seen the term used quite a bit and while i have an idea what
it is, i'm not 100% sure how to use it.

it's a jig. i have an idea that this is similar to a template but i
cannot seem to find any sites that explain what jigs are and how they
work so that i can fully understand.

yes...i know it's stupid for me to think this way but i can't figure
out why someone would spend a chunk of time making a jig to drill a
hole, for instance.

please pardon my ignorance...i really want to learn. oh and my first
real project? building a headboard for my queensize bed.

thanks!
john