Here is a great free online guitar tuner. This is a flash based guitar tuner. All you have to do is click the note and then tune the corresponding string on your guitar. You should always make sure your guitar is in tune before practicing
You can use the arrows to switch from standard tuning, to drop D tuning, to double drop D tuning, to DADGAG tuning, to open C tuning, to Open D tuning, and finally, to open E tuning.
thanks www.Kiimi.com for the tuner!