- In a large resealable plastic bag, combine the zucchini, yellow squash, onion, tomatoes and 1 cup Italian dressing.
- Seal bag and refrigerate for 30 minutes.
- Preheat grill to medium.
- On metal or soaked wooden skewers, alternately thread sausage and vegetables.
- Grill for 10 minutes or until browned, turning frequently and basting with remaining Italian dressing.