Combine all of the ingredients in a blender, and blend until very smooth and creamy. Adjust sweetness to taste, if necessary, keeping in mind that the frozen popsicles will taste less-sweet than the room-temperature batter.
Pour the batter into 8 popsicle molds (this may vary, depending on the size of your molds), place a stick in the middle of each mold, and freeze for at least 6 hours, or until solid.
To remove the frozen popsicles, I like to fill my kitchen sink with hot water and submerge the molds for about 20 seconds to loosen. They should pop right out! Store in a sealed container in the freezer until ready to serve.
*Note: The salt is only necessary if you're using unsalted peanut butter.