Google it. But, in lieu of that, you might try:
http://www.ultimate-guitar.com/lessons/ (check out the "for beginners" section).
But really, there are lots of guides to everything and you should read around as much as you can.
You need to learn, in order:
How to tune your guitar (
this helps)
What the different bits are, and what they do
How to look after your guitar (
very important, I can't stress this enough)
How to read tab notation
Some basic chords
How to do barre/power chords
Then just pick a basic song that you know and learn it. Then repeat. Then practice. Then practice some more. Maybe try a few more songs, but keep practicing. It's not going to be easy, but you'll get it. I started out on Beatles songs, you may want to try some of those.