A way to find whether your IP address has correctly been set is to look at the connected clients of your router. That should list the IP address of your Raspberry Pi.
To retrieve the assigned IP address, you can also execute the following command on your Pi:
The RPi Advanced Setup article on eLinux describes how to change to set a static IP address:
The quick way: assign a static IP address to your Pi. This is simple, but runs the risk of clashing IP addresses with other devices on your network since your Pi's address will no longer be managed by DHCP. I haven't tried this myself, but here's some instructions from Andrew Munsell. He's using 192.168.1.222 for his Pi, since that's outside the range assigned by his router. Change this address to whatever suits.
You can do this in Debian Squeeze on the Raspberry by modifying the /etc/network/interfaces file.
I removed the original
iface eth0 line and replaced it with the following:
iface eth0 inet static
On reboot, your Pi should now be using the static address specified in