Eggplant-And-Feta Pitas

eggplant slices; (1/2-inch-thick)

vegetable cooking spray

pita bread rounds; (6-inch)cut in half

tomato slices; (1/2-inch-thick)

crumbled feta cheese with peppercorn

(1 oz.) 1/4 C. chopped red onion

large fresh basil leaves; thinly sliced