This webcam is built-in to your eee PC 900 and should automatically be detected by Windows XP. To check if its installed have a look in My Computer under USB Video Device.
As far as we are aware, there are no drivers for this webcam. However, if you can;t find your webcam device in the device manager, you may need to turn-on the webcam in the BIOS settings.
Sorry. Restart your PC. While its starting up (before Windows loads up), Press F2. Thi will get to the BIOS settings. Select "Advanced" from the menu. Set "OS Installation" as "finished". Onboard Device set that to "Enable". Then press F10 to save the settings.