Okay-- so Biglaw 1L SA pays $2,000-$3,000 a week.
What about Mid or Small firms? Would someone in the middle of the class at Michigan or Cornell be able to get a paying job at a smaller firm and what would that pay?
Would there be a difference between Michigan and Cornell for landing a 1L summer job?
It will all come down to your resume. If it is good, the fact you're going to a great school will bolster an already-strong chance at getting an interview. If it is not overly impressive, your fall grades will provide you with an opportunity to stand out in the crowd. So it will come down to you, basically -- not your choice of law school.
And if you're interested in the money amounts, look up firms in your desired location on NALP. All of them state what the pay is. It's usually the same for 1Ls and 2Ls though sometimes it varies (NALP will say if there is a difference). The salary seems to generally be what you'd be getting weekly if you were a regular associate. This is how it is at the firm I'm working for, anyway.