How do I quit and when?

This is the 4th week I have been working? It was supposed to be a 2 week temporary thing only until this other lady comes. She came and lasted a week. She didnt show up one day to work. I need a part-time job because I'm going to be busy with my grad school applications and GRE's and such. I'm afraid my boss won't agree to me going part-time now since at interview I told him I'll be available full-time, year round (I didn't realize how much time this job would require). But things change so... This is a small law firm with three other people who are really close. I don't know when to tell him and I'll feel bad if they hear itt oo (they will, it's a small office too) HELP!

yeah but this job is almost 50 hours/week not even 40. I am sooo bored here, I just sit here and answer Yahoo questions. I don;t know why he wanted another person cause there sure isn't work for one

just go ahead and tell them, i think they will understand, ppl are used to seeing other move on with their lives even if they don't have the balls to

sounds like you screwed yourself when you hired and told them you could work full time all year, and in a month want to back out of it and go to part time. if it were me, and you pulled something like that, i would be saying "adios" for the simple fact is apparently you lied about your availability just to get the job. and you didnt realize how much time the job would require? comeon, it's full time, and everybody knows that ful time is anywhere between 32 and 40 hours.
i would so much be pulling a donald trump on you and saying "you're fired".