I believe you are talking about the Research Experiences for Undergrads (REU) program funded by the NSF. I participated in this program at the University of Chicago back in 1997, but it was for physics. My gpa at the time was 4.0 but that's the only real stat they recieved in the application (no high school stuff). You send letters of recommendation, and write a short essay, and I think those weigh pretty heavily. It all depends on what school you apply to as well though...they are allowed a wide range of freedom in choosing whom they want to participate in their program.
Here is the NSF webpage discussing REUs:
<a href="http://www.nsf.gov/home/crssprgm/reu/start.htm" target="_blank">http://www.nsf.gov/home/crssprgm/reu/start.htm</a>
My experience working in the High Energy Physics department at UofC was amazing!! And like you said, there were Nobel laureates thick as thieves!!! I had to present a talk on my research at the end of the summer, with Nobel laureates in the audience!! I'd highly recommend anyone to participate in this type of program if possible.
Also, apply to more than just one program...I applied to about five of them, with UofC my first choice, and I got rejected from all of them BUT UofC!! I was still a freshman at the time though, and usually they want enterring seniors. Apply quickly too...deadlines for schools start as early as the end of January.
Best of luck to you!!!
Raina