I love playing guitar, whether for people at parties or in the quiet solitude of my home. I also enjoy learning new pieces, whether from traditional sheet music or from the wide range of guitar tabs available on the Internet (most of which are not that good). Yet after years of playing, I still occasionally come across a weird chord that I haven't played in ages. Like many students of the instrument, I learned a majority of chords from Mel Bay guitar chord books. The drawback of these books is that there is no sound accompanying the strum, so it is hit or miss whether your fret fingering is correct. However, with the release of portable music apps like Agile Partners' GuitarToolkit, chord formation and sound are no longer a mystery.