Yes, beep is a Scrabble word!
...and is worth 8 points in Scrabble, and 10 points in Words with Friends
beep
Verb
1. Make a loud noise
2. Call, summon, or alert with a beeper
Noun
1. A short high tone produced as a signal or warning
What Scrabble words can I make with the letters in beep?
3 Letter Words
2 Letter Words