To play the minor pentatonic scale, start with your first finger on the fifth fret of the sixth string. Play that note, then put your fourth (pinky) finger on the eighth fret of the sixth string, and play that. Continue to play the scale, being sure to play all notes on the seventh fret with your third finger, and notes on the eighth fret with your fourth finger. When you've finished playing the scale forwards, play it in reverse.
Congratulations! You've just played an A minor pentatonic scale. The scale we played was an A minor pentatonic scale because the first note we played (sixth string, fifth fret) was the note A.
Now, let's use the exact same scale pattern to play an A major pentatonic scale, which has a totally different sound. To use this pattern as a major pentatonic scale, the root of the scale is played by your fourth finger on the sixth string.
So, to play the A major pentatonic scale, position your hands so that your fourth finger will play the note "A" on the sixth string (which means your first finger will be at the second fret of the sixth string). Play the scale pattern forwards and backwards. You're now playing an A major pentatonic scale. Strum an A major chord - it should sound like it "fits" with the scale you just played.
Once you're comfortable with the fingering, try sliding back and forth between the A minor and A major versions of the scale using this mp3 of a 12-bar blues in A as your background rhythm track. The minor scale sounds more blues-y, whereas the major pentatonic has a more country sound.