Best way to quit/leave a job?

[MandyPepperidge]

Not really a job in my case, but rather an internship. I took an unpaid internship this semester in a field I thought I might possibly be interested in. There was also an strong hint at offering me a job or helping me find a job if all went well.

I've been there about three weeks and feel ambivalent towards the experience. My bosses also took on another intern to share my responsibilities, making them the only team with two interns.

On top of that, I just accepted a job offer that is completely unrelated to my internship. This internship is adding nothing to my resume and would never add to my employability in the future.

So how do I leave? I have never quit anything in my life nor left a job other than to go to college. I'm sort of at a loss as to what to say. Should I maybe stick with it a little longer? I like the people I work with, but I'm not enjoying my work and I'm not even getting paid or receiving college credit.