For Windows users
Download and install the latest image of Debian “squeeze” from the Raspberry Pi Downloads Page
Power it up and wait while it boots. If you get an error message (e.g. things like ‘Raspberry Pi kernel panic not syncing fatal exception in interrupt) then try removing your keyboard and mouse to see if it will now boot (some peripherals can cause errors).
After around 20 seconds you should end up with a login prompt. Enter the default user name ‘pi’ and default password ‘raspberry’ to log in.
You are now at the Linux command prompt.
Enter the command ‘startx’ and the fancy X window system graphic user interface will load.
If you’ve connected the Pi to your network it will automatically use DHCP to connect to and will be ready to connect to the Internet.
To get linux superuser privileges
At the command prompt (before entering startx) enter the standard Linux command ‘sudo’ (no password required).