In deep bowl, combine first 9 ingredients for herb marinade; mix well.
Add meat cubes and stir to coat.
Refrigerate overnight or let stand at room temperature 2 or 3 hours, turning meat occasionally.
Fill skewers, alternating meat cubes with chunks of green and red pepper and onion slices.
Broil over hot coals to medium rare doneness, brushing frequently with melted butter or margarine.(Use rotating skewers or turn often on grill.)