This recipe from allrecipes.com sounds really good:

Slow Cooker Cranberry Turkey Breast

Serves 8

1 (16 ounce) can cranberry sauce
1 (1 ounce) package dry onion soup mix
1/2 cup orange juice
1 (3 pound) boneless turkey breast
Directions

Place the cranberry sauce in a bowl, and mash. Mix in the onion soup mix and orange juice together until the mixture is well combined.
Spray the inside of a slow cooker with cooking spray, and place the turkey breast into the cooker. Pour the sauce ingredients over the turkey breast. Set the cooker on Low, and cook until the turkey breast is very tender, about 7 hours.

Follow this link to my last year's post about how to soak your turkey in brine for maximum juiciness:

Brining Your Turkey