Type up a letter stating that you plan on resigning and give your last day. Offer to help train your replacement if needed. Thank them for the opportunity and mention how much you learned. Print it, put it in an envelope, go in to work, hand it to your boss and say I just wanted to give you this. It is my two week notice. I had a great time here and learned a lot. If he/she asks, just say you want the rest of the summer to prepare for college. You might also want to leave your options open for winter break and next summer by saying something like you would be available over school breaks if needed (just to pick up some cash - college can be expensive).
You are not disappointing anyone. Employees are easily replaceable.
You just write out the usual notice such as the following,
Dear Mr. XXX
I am giving 2 weeks notice and will leave on YYdate.
Then say something nice such as I have enjoyed working for company and have gained valuable experience for my future.
Sign your name.
Give them only two weeks notice and don't worry too much. After all if they did not need you two weeks notice would be yours. Good Luck.
You just tell him. Elaborate "reasons why" don't need to be part of the discussion. Just say you're preparing to return to school.
