online resources
Tuner
Download this free chromatic tuner for your phone or tablet.
Metronome
www.metronomeonline.com is a free online metronome that is awesome and that I regularly use myself when I accidentally leave my metronome at school. It's pretty awesome.
Here is another free web-based metronome that also offers an app.
Music Racer
Games that help learn Note Name, Fingerings, and Musical Terms/Vocabulary