So I'm going to purchase the Nikon D90 when I return home and as I know nothing about DSLR related stuff like lenses, I'm going to need help.

For Macro pictures I know that I'm already getting the Tamron 90mm one as I've read that's one of the better ones that you can get for this camera.

The next dilemma I have is the camera comes with the Nikon 18-105mm VR(Vibration Reduction) and they also have the Nikon 18-55mm VR. I'm assuming that the 105 has a better zoom, and I'll be using this until I get around to getting an 18-200mm or even an 18-300mm I think. Any help would be greatly appreciated.

I could also use some information regarding a different flash, but what I'm confused on is whether the flash attaches to the camera or something else? Thanks for any help.