For Windows XP and ranih versions:
Как узнать свой IP и MAC адрес в сети MajaNet
For Windows Vista and Windows 7:
How to find you IP address (windows 7)
Universal way: 1. Hold the keyboard Winows button (the button on the window), and hold the first button we press Latin (anliyskoy) letter R 2. In the window that appears, write - cmd 3. Hit Enter or click OK 4. In the black box, write - ipconfig / all 5. Looking for a place - IPv4 * -Here's your IP. * There may be a few, but most likely you will have one.