Yes, tune is a Scrabble word!
...and is worth 4 points in Scrabble, and 6 points in Words with Friends
tune
Verb
1. Adjust for (better) functioning
2. Adjust the pitches of (musical instruments)
Noun
1. A succession of notes forming a distinctive sequence
2. The property of producing accurately a note of a given pitch
3. The adjustment of a radio receiver or other circuit to a required frequency
What Scrabble words can I make with the letters in tune?
3 Letter Words
2 Letter Words