The Minor pentatonic is the most popular scale used by guitar players. Usually it is the first scale a guitarist learns even before the major scale. The reason for this is that it is used so frequently in rock, pop and blues songs, that guitarists copy riffs of songs they like first before they even know that it is in fact a scale.
This scale can be used just about anywhere. It is easy to remember as it only has 5 notes , and the fingering can be mastered very quickly. The Minor Pentatonic is really a basic Blues scale without the flatted 5th. Check out the BLUES SCALE page for more information and fretboard fingering patterns.