Preheat oven to 350°F. Halve the pickles lengthwise. Carefully scoop out the centers. Pat dry.
In a medium bowl combine cream cheese, cheddar cheese, jalapenos, garlic powder, salt, and pepper. Transfer cream cheese mixture to a re-sealable plastic bag. Snip the corner of the bag and pipe cream cheese mixture into the pickle halves. Wrap each pickle half with ham and secure with a toothpick, if needed. Place pickles in a foil-lined baking pan. If desired, brush with jam.