Yes, pie is a Scrabble word!
...and is worth 5 points in Scrabble, and 6 points in Words with Friends
pie
Noun
1. Dish baked in pastry-lined pan often with a pastry top
2. A prehistoric unrecorded language that was the ancestor of all Indo-European languages
What Scrabble words can I make with the letters in pie?
2 Letter Words