By default, the Nexus One uses a dynamic IP address when you connect to a wireless network. If a static address is desired, you are only a few steps away.
1. Go to the Home screen.
2. Select the Menu key.
3. Select Settings.
4. Select Wireless & networks.
5. Select Wi-Fi settings.
6. Select the Menu key.
7. Select Advanced.
8. Check the Use static IP checkbox.
9. The IP address, Gateway, Netmask, DNS 1 and DNS 2 fields will no longer be ghosted out. Fill in the desired values.
10. Connect to the desired wireless network.