Many guitar makers have realized that tiny fingers and hands will not reach around the neck of most guitars. Small beginner guitars may be the perfect instrument for your preschooler. Guitars are just fun. They light up a child's eyes, and small children take to them immediately. For preschoolers, buy them a brightly painted guitar that fits them. Have it tuned to a major open chord by a guitarist or do it yourself. By tuning to a major chord, all the child has to do is strum the guitar with her right hand to make music. From here, simple one-note fingerings can be taught to play simple nursery rhyme songs.
One preschool instrument that is easy and affordable is the common Flutophone. Also known as a recorder, it is a flute-like instrument that has ten holes. The child places the mouthpiece between his lips like a clarinet, blows air through it and fingers the notes on top. Flutophones are easy to play by ear, and most students can soon be playing compositions of their own or some of the more advanced students may even master, "Twinkle Twinkle Little Star." Lessons are readily available for Flutophones online or you can buy books at any music store. Some schools even include Flutophone lessons in their curriculum.
No other instrument plays like a set of drums. A child can have no musical ability whatsoever--not many preschoolers do--and still get a tremendous amount of satisfaction from drums. Let them bang on the drums at first for fun. Then teach them how the individual drums apply to a song, for instance, show them that the snare, the drum right in front when you sit down, is to keep the beat. Let them count it out as they hit it, one, two, three, four. Let them stomp the base pedal with their foot, and listen as the bass drum resonates. When they get used to how drums work, introduce them to some short lessons.
Piano is often a child's first instrument. When you introduce piano lessons at an early age to a child, it gives them appreciation for music in its entirety. Pianos are arranged on a chromatic scale. This means that notes progress up the keyboard in a regular sequence of notes including all the sharps and flats. Children can play and then hear when a note goes flat or sharp, when the note doesn't quite sound right. When they learn this distinction, they are already light-years ahead of their preschooler counterparts.