what chicken and how do you prepare it for grilled chicken?!

It doesn't do any good to look for pink in chicken. The meat can be fully cooked and still have a pink tinge. Temperature is the only sure-fire way to determine when chicken is cooked, unless you have been doing it for twenty or thirty years and have a "feel" for it.
You can grill any chicken, breasts are clean and easy, but tend to dry out if not watched carefully. Thighs are more moist, but also fattier and have a bone. Thighs are good if you plan on shredding your chicken. Chicken tenders (part of the breast and kind of expensive for my taste) are very thin and likely to dry out or burn.
You don't need to precook your bird parts, but cook them over a low flame so the inside has a chance to heat up before the outside turns to char. Indirect heat would be even better, but let the fat drip on the hot coals so you get that unique char-broiled smokey flavor.
Yes, Italian dressing is a good, easy marinade.

Chicken breast or chicken tenders would work well. You want something with out a bone in it if your are putting in on a sandwich. You just put it strait on the grill, No need to bake it first. That would just dry it out. Just make sure the internal temp. of the chicken reaches 160 degrees F and also make sure there's no pink.

Personally i love BBQ sauce on my chicken but there are a lot of marinade you could buy in the dressing isle at the grocery. Italian dressing is great on its own. You could also do a citrus marinade with lemon or lime or orange. So many options.

Experience (:

I'm assuming you mean sliced chicken and not chicken patties.

Your easiest route is by just buying pre-grilled chicken found in your local grocery store (Vons, Albertsons, etc.) Those are very juicy, has lots of flavor, and is cheap. You can also sprinkle smoked paprika on top to give it more flavor.

I've done it before.

How should you cook grilled chicken? By grilling it. Marinate some boneless chicken breasts for a few hours (Italian dressing works great) and grill it.

Grilled Chicken Reubens Recipe

2 boneless skinless chicken breast halves (4 ounces each)
4 slices Swiss cheese
4 slices rye bread
3/4 cup sauerkraut, rinsed and well drained
1 tablespoon butter, softened
Directions
Place chicken on an indoor grill coated with cooking spray; grill for 3-4 minutes or until juices run clear. Place a slice of cheese on each of the two bread slices. Slice chicken; place over cheese. Top with sauerkraut and remaining cheese and bread.
Spread butter over both sides of sandwiches. Cook on indoor grill until bread is browned and cheese is melted. Yield: 2 servings.

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Grilled Chicken Sandwiches Recipe

4 slices marble rye bread
2 slices (3/4 ounce each) reduced-fat Swiss cheese
6 ounces thinly sliced deli smoked chicken breast
1/4 cup egg substitute
1 tablespoon fat-free mayonnaise
1 tablespoon Dijon or spicy brown mustard
Directions
Top two slices of bread with cheese and chicken; cover with remaining bread. In a bowl, whisk the egg substitute, mayonnaise and mustard; spread outside of sandwiches with egg mixture. In a large nonstick skillet coated with cooking spray, cook sandwiches on both sides until golden brown. Yield: 2 servings.
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Grilled Chicken Club Pitas Recipe

Ingredients
3 tablespoons mayonnaise
3 tablespoons honey
3 tablespoons spicy brown mustard
1/4 teaspoon salt-free garlic seasoning blend
2 boneless skinless chicken breast halves (5 ounces each)
2 whole pita breads
1/2 cup shredded lettuce
2 bacon strips, cooked and crumbled
2 slices Swiss cheese
Directions
In a small bowl, combine the mayonnaise, honey, mustard and seasoning blend; set aside 3 tablespoons. Pour remaining mixture in a large resealable plastic bag; add chicken. Seal bag and turn to coat; refrigerate for at least 1 hour. Refrigerate reserved mayonnaise mixture until serving.
Grill chicken, covered, over medium heat or broil 4 in. from the heat for 5-7 minutes on each side or until a meat thermometer reads 170°. Cut chicken into 1-in. strips.
Spread reserved mayonnaise mixture over pita breads; top with the lettuce, chicken, bacon and cheese. Yield: 2 servings.
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Grilled Chicken Cucumber Salad Recipe

Ingredients
1/2 cup cucumber ranch salad dressing
1/4 teaspoon dill weed
2 boneless skinless chicken breast halves (6 ounces each)
1 medium apple, cored and cut into 1/4-inch rings
2 cups mixed salad greens
1-1/4 cups sliced cucumber
Directions
In a small bowl, combine salad dressing and dill. Pour 1/4 cup into a large resealable plastic bag; add chicken. Seal bag and turn to coat; refrigerate for 20 minutes. Refrigerate remaining dressing.
Drain and discard marinade. Using long-handled tongs, moisten a paper towel with cooking oil and lightly coat the grill rack. Grill chicken, covered, over medium heat or broil 4 in. from the heat for 6 minutes on each side or until a meat thermometer reads 170°. Keep warm.
Brush 1 tablespoon dressing over apple rings; grill for 1 minute on each side. Divide salad greens and cucumber between two serving plates. Slice chicken; arrange chicken and apple rings over greens. Serve with remaining dressing. Yield: 2 servings.