The Boy Is Mine by Brandy & Monica is in C#m at 100 beats per minute and runs 3:17 across 51 bars. It uses 2 chords — F#m9, C#m9. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? The Boy Is Mine guitar melody tab.