Sprinkle the fish with 1 t oregano and salt. Marinate in refrigerator 2 hours, turning occasionally.
Prepare grill.
Cut 2 slits in each steak. Insert 2 garlic quarters into each slit. Place the fish on a grill rack coated with cooking spray. Grill 4 minutes on each side until fish is medium-rare or until desired degree of doneness.
Combine 1 t oregano and the juice in a medium bowl. Dip grilled fish into juice mixture; place on plate. Add oil to remaining juice mixture; stire well with a whish. Spoon juice mixture over fish; sprinkle with pepper. Garnish with oregano sprigs, if desired.
Note: There's a lot of lemon in this dish, so be sure to choose a white wine that has a bit of citrus zing itself (avoid red wines; they clash badly with lemon).
Source: Cooking Light Magazine July 2001