In a medium saucepan, melt margarine. Add sugar and corn syrup.
Stir and bring mixture to a boil. Let boil for 5 minutes.
Remove from heat and add vanilla and baking soda. Stir until fully combined.
Lay popcorn out on two cookie sheets. (Half on one and half on the other. You can use one for all of it, but I find I have an easier time stirring if I use two.)
Pour caramel mixture over popcorn. Stir to cover the popcorn.
Bake in a 200° oven for 1 hour, stirring every 15 minutes.
Cool on foil or wax wax paper.
When caramel corn is completely cooled, prepare the chocolate. Place milk chocolate in a microwave-safe bowl. Microwave in 30 second increments, stirring between each interval, until completely melted.
Transfer melted milk chocolate to small plastic baggie. Seal.
Cut a small corner off the bag and drizzle milk chocolate over popcorn.
Repeat steps 8-10 with white chocolate chips.
Allow chocolate to cool and harden before serving.