Before you can play anything you need to have a tuned guitar.
The standard tuning for a guitar is:

STRING NOTE
6th string(the fat one) E
5th string A
4th string D
3rd string G
2nd string B
1st string(the thin one) e

Order Your Guitar Tuner Here!

We suggest buying an elctronic tuner that does all the work for you. A good tuner can go for 10-50 bucks at any guitar retailer. To make things really easy, here is a link on Amazon.com which you can click on and order a great little electronic guitar tuner for under $10.

If you want to hear the pitches of the strings, try this link:
http://www.710.com/reload/fun/tune.htm

If you don't want to get an electronic tuner, then. . . .

1. First thing you need to do is get one string in tune(preferably E).
2. Then all you've got to do is this:
Put your finger on the 5th fret on the E string. That should match the tone on the open A string.
Turn the A tuning key until they match.
Put your finger on the 5th fret on the A string. That should match the tone on the open D string.
Turn the D tuning key until they match.
Put your finger on the 5th fret on the D string. That should match the tone on the open G string.
Turn the G tuning key until they match.
Put your finger on the 4th fret on the G string. That should match the tone on the open B string.
Turn the B tuning key until they match.
Put your finger on the 5th fret on the B string. That should match the tone on the open e string.
Turn the e tuning key until they match.

Hear the pitches here. Maybe not so easy for some of us. Be patient, it just takes a little time before our ears learn the tones and their relations to each other.

or check out this online tuning site: