i spent some time to modify the desktop of my nexus one. On the right site, you can see how it looks like and now i will give you a short introduction how to achieve this.
Wallpaper: You can download the wallpaper here.
Icons: A set with the base icons can be found here (there are other colors too). Even more icons, for different apps, are located here (only green ones). To make your own icons, you can find the psd file here.
Dock: The dock-bar image: here
Used Apps: Desktop Visualizer, to add custom icons to your desktop apps. LauncherPro a home replacement which is a lot smoother and is more customizable. Multicon Widget to make the icons on your desktop smaller. Weather Widget Snowstorm.
LauncherPro allows you to change to dock-bar background and the icons by itself so you can simple change the look in the settings menu.
Its a bit tricky to have the icons on the desktop either. As you can see the icons are smaller as the normal desktop icons would be. You can achieve this by adding the 1x1 or 1x2 Multicon desktop widget. Then click it to open the configuration screen where you can select which icons to show. Click one of the four icons, then choose the "Shortcuts" tab and select "Desktop Visualizer". To hide the icon placeholders you don't need just add a blank icon to it. You can find this blank icons in the configuration tab "Other", its called
If you still have questions feel free to ask.