I want to learn how to play those instruments and I already know how to play 8 of the chords on the guitar. I have an old keyboard at home and I really want to learn more about these instruments! Thanks:)
http://www.youtube.com have guitar tutorials. http://www.ultimate-guitar.com contains guitar tabs of many different songs (only good if you can read tab). http://www.theguitarclass.com is a website dedicated to teaching people how to play the guitar through video lessons and also has forums and chat room. But you have to register first and it costs $5.95 per month.
I found this download of a guitar tutorial but not sure how good it is…http://www.brothersoft.com/downloads/guitar-tutorial.html
For Piano…This website http://www.lofthouse.com/music/piano/tips.html gives you the basics for learning to play.
Here is a Piano Tab website…http://www.pianotabs.net/tutorial.html which also shows you how to read and write tabs.
Here's an online book about learning to play…http://www.amazon.com/Piano-Handbook-Complete-Guide-Mastering/dp/0879307277
Good luck with learning. 