In a medium mixing bowl, add peanut butter, sugar and butter and mix until smooth.
Add crushed pretzels and mix well (to crush pretzels, place in storage bag and roll with a rolling pin; a food processor can also be used).
Using a small scoop (or 1 tablespoon) roll the peanut butter mixture into balls.
With your thumb, press a light indentation into the top of each. TIP: dip your thumb into water to prevent the peanut butter mixture from sticking.
Drop ¼ teaspoon of jam into each indentation, then fold up the peanut butter mixture over the jam. Alternatively, a small amount of the peanut butter mixture can be placed over the jam. Just be sure to use a little less than a tablespoon when dividing them out.
Roll them back into balls and place on a cookie sheet. Place in the freezer for 30 minutes.
Meanwhile, melt chocolate in a double broiler.
Once the peanut butter and jelly pretzel bites are firm, remove from freezer and dip in warm chocolate.
Place chocolate covered balls back on cookie sheet or on a rack to dry.
Keep refrigerated until ready to serve.