There are 3 main types of harmonics:
natural harmonics
artificial harmonics
pinch harmonics
Pinch harmonics can be achieved on an acoustic. If you can get them on an acoustic, they will scream on an electric. For examples of pinch harmonics, listen to some Killswitch Engage, or Vai's 'The Attitude Song'.
Natural harmonics are simple ratios of a string length. You get them by touching a string above a fret (not holding the note in) - exactly above the actual fretwire. The strongest natural harmonic is at the 12th fret, as this is half the string length (ratio of 1:2), then the 7th, 5th, and 4th frets (4th is the same as the 9th fret harmonic).
Artificial harmonics are when you get a harmonic whilst holding a note in e.g. if you are holding in at the 3rd fret, you could get a harmonic at the 15th fret (an octave; half the string length from the 3rd fret to the bridge).
The classic rock track with harmonics is, of course, Satriani's 'Summer Song'. But it isn't the easiest piece of music to play on the guitar. Banana Mango has a great accompanying part that is full of harmonics.
Actually, you should just buy Joe's 'Time Machine' album and enjoy it
