Well, I'm packing tonight for my interview at UCLA's ACCESS biology program! I'm leaving from Boston tomorrow at 7:50 AM and coming back Tuesday morning at 6:45 AM. (My postdoc at the lab told me I don't have to come in on Tuesday until after I've taken a nap. This may sound nice, but is in fact good sense -- you really don't want someone careening around the lab after pulling an all-nighter on a Boeing 757. Way too many dangerous chemicals and worth-more-than-your-life machines.)
A grad school interview is a pretty good sign -- it means the department is excited about your application and wants to get to know you in person. I'll be meeting this weekend with four potential PhD advisors... and eating a lot of free food (and wine! eek, free wine!) and staying in a classy hotel on Sunset Boulevard. And it's all free, from the airfare to the hotel to the sunset walk on the beach. As you might imagine, these weekends are half interview and half recruitment, and by all accounts they're pretty fun.
In other areas of my life (aka lab), things are going spectacularly. I developed a couple of really pretty Western blots, and my postdoc thinks we'll be ready to publish after a few more experiments. Amazingly, I've been working on this project since November 2004... I can't believe we're almost ready to write up the results. Talking about lab reminds me that I need to talk about...
Grad school admissions:
Joanie and Chris wanted to know about graduate school admissions. I will make the disclaimer that all I know about is biology admissions -- I'm currently asking around to see if I can find one of my friends who can give intelligent advice on engineering grad school admissions (both for you guys and for my favorite airplane nerd, who'll be applying next year), but in the meantime I will present what I know about graduate school admissions in biology (and what's true for biology is pretty true for all of the natural sciences).
First, you definitely don't need a 4.0 to be admitted, even to the very tip-top programs. You likely need above a 3.0 (although one of my favorite professors told me about a student with a 2.9 who got into Harvard's program), but GPA isn't as important as research experience. Period. I have a 3.5, and I'm interviewing at five of the top seven programs in biology -- and that may be six, since I'm still waiting on one.
You do want to get involved in research early. Some students wait until their senior year to get involved in a project, at which point they need to start applying to graduate school and thinking about graduating and stuff. I got started the summer after my freshman year, and I think it was a really good decision. At MIT, you can start UROPing as early as freshman year (although many labs like you to have taken a lab class before you descend upon their expensive lab equipment). Importantly, you want to get really involved in a project -- some of my friends at other schools have had "research positions" where they washed glassware; washing glassware, although useful for the lab, is not going to get you into graduate school. Publication, particularly in high impact factor journals, can really help you, although most applicants aren't published by the time they apply.
Getting really involved in a research project will help you get recommenders who know what you're like in the lab. This is a pretty important part of the package, since the members of graduate admissions committees are professors and they're interested in hearing what their colleagues think of you as a scientist.
Most programs (and pretty much all of the really good ones) require the GRE general test, graduate school's answer to the SAT. If you did well on the SAT, you will probably do well on the GRE -- they're pretty much the same test, but GRE math is easier (8% of test-takers get an 800!) and verbal is harder. The GRE really isn't all that critical for getting into grad school. A good score probably isn't going to help you significantly, although a bad score can hurt -- for example, the average engineering applicant gets a 750 in math. If you get a 500 in math and you want to go into engineering... you might be SOL. Some disciplines have GRE subject tests and some don't; you're only expected to take a GRE subject test in a subject in which you majored.
Extracurriculars aren't considered at all for graduate programs (except research, of course) -- none of my applications but one even had space to write them down. And you probably won't have to write a billion essays like you did for undergrad; most programs require a "statement of purpose" explaining your research background, research interests, and purpose in applying to graduate school.
To answer GP, I applied to nine graduate programs: BU, Berkeley, Caltech, Harvard, Michigan, MIT, Stanford, UCLA, and UCSF. I applied for either cell biology or neuroscience (or both) at all those schools. I got interview invitations from all the schools, and ended up being accepted at all but one.