Congrats on the D700 - excellent camera.
You obviously need to select RAW format on your camera but don't need to DL anything else from it.
Go to
http://www.adobe.com/support/downloads/detail.jsp?ftpID=4621 to find the latest version of Adobe Camera Raw.
DL your pictures as normal but when you select a NEF image to open it will take you into the Adobe Camera Raw (ACR) plug-in. Not a lot to learn there, you'll soon get the hang of it through trial and error. Click on Open Image when you're done with basic processing and the NEF will create an XMP file (known as the sidecar file) which contains all the things you've done to the image in ACR. You will also be opening the NEF in CS4 - be aware that if you selected 16-bit in ACR then some CS4 functions will not be available.
Do your editing - but you cannot save as a NEF (only your camera can do that) so save the NEF as a TIFF or PSD if you want to retain all the quality that you've captured by using RAW. Some people immediately save as a JPG - totally pointless, you might as well have let the camera save as a JPG for you. Keep the TIFF or PSD file as your "Master" - just make JPGs for particular tasks (email or web). Some people then keep backups of all their Master files, like keeping your negatives safe.
Installation of ACR
To open a DMG file:
Double-click the file. This will open Disk Copy, which mounts the image on your desktop.
To install with Adobe Creative Suite 4 or Photoshop CS4:
Automated installation on Mac or Windows®:
1. Select Updates... from the Help menu
2. Follow the on-screen dialogs to download and install the latest available Camera Raw update
Manual installation on Mac:
1. Exit Photoshop CS4 and Adobe Bridge.
2. Open the download file and double-click Setup, and follow the on-screen instructions.
3. Launch Photoshop CS4 or Adobe Bridge.