I saw Cloverfield at an advanced screening on Wednesday, and last night. I won't review the movie yet, other to say it was awesome, but I'd like to offer some tips for when you go to see it.
[highlight to see spoilers]
1. You may get nauseous. I did. I didn't throw up or anything, and I was fine when I saw Blair Witch, so YMMV. The second time I saw Cloverfield, I took a non-drowsy Dramamine and I was fine.
2. Look for someone passed out on a couch at the party. It's [Jamie Lascano!]
4. Something to look for in the final scene. [When Rob and Beth are at Coney Island, look out into the ocean and you can see something fall into the water.]
3. Stay for the end credits. All the way to the end. [There is whispering at the end that sound's like Rob saying "Help Us". Someone recorded the audio and played it backwards, and it sounds like he is saying "It's Still Alive"]
4. Have Fun!