Have a microphone?  Want to record yourself playing your instrument, singing, talking?  Click here:  http://audacity.sourceforge.net/

Need a metronome at home?  Click here: http://www.metronomeonline.com/

Need to practice some Music Theory?  Click Here: http://www.emusictheory.com/ and click on free theory drills.  You can learn to read music, do rhythms, and lots more!

Want to jam with your guitar with someone in another state? country? try this, not sure how good it is, but looks interesting: http://www.ejamming.com/home/

This is really fun to play with too!  http://tones.wolfram.com/generate/advanced.html?instrumentation

President's Own - some music history - about american music:

http://www.marineband.usmc.mil/learning_tools/discover_american_band_music/1801.htm