This is from Mr. Food's A Little Lighter cookbook; it's very yummy

1 Medium sized cucumber, cut into 1 inch chunks

1 Cup reduced fat sour cream

1 Cup light mayonaisse

 1/2 tsp. garlic powder

1/4 tsp. black pepper

In a blender or food processor, combine all the ingredients and process until smooth and creamy.  Store in the refrigerator in an airtight container until ready to use.