Raspbmc is probably the easiest way to get XBMC onto your Raspberry Pi, but you can also use other install options such as the Linux based OpenELEC set-up or Xbian.
You will need the following before starting:-
4 GB SD Card (FAT formatted)
Mouse with Wireless USB Adapter
How To Install Raspbmc using Windows
Connect your SD card to the PC.
Firstly download and extract the Raspbmc Installer for Windows, MAC or Linux.
Run the installer by double clicking the installer.exe and follow prompts.
From the menu choose your SD Card and click install.
Remove the SD Card from the computer.
Connect the SD Card to the Raspberry Pi and connect to TV using HDMI.
Go through the installation procedure to install XBMC onto the Pi.
This guide is to install XBMC with OpenELEC for Raspberry Pi from a linux desktop.
The first thing you should do is download the latest stable build of OpenELEC for Raspberry Pi here. Once it's downloaded, you'll have a archive ends in .tar.bz2 - This file contains the OpenELEC installer files. You will have to extract the files from the archive in order to use them.
Now open the folder you downloaded the file to, right-click on it and select 'Extract Files...'. This will create a new folder with the installer files in it.
you now need to open a terminal (Command Prompt). Navigate to where you've downloaded the files, then into the folder the extraction has created:cd /home/username/Downloads/OpenELEC-RPi.arm-3.0.1.tar.bz2
Now, pop your SD card in that you're going to use and find out what device it is (after you've inserted the SD card, use dmesg | tail to find out. It should be something like /dev/sdX).
Next its time to create the installation key. You'll need superuser privileges to do this, whether you use the root user or sudo. Either way, you need to execute the following command:sudo ./create_sdcard /dev/sdX (where /dev/sdX is the device you looked up a moment ago)
It's very important that you make sure you have the right device as it will be wiped as part of the process.
For example, it's extremely unlikely that your device will be /dev/sda, as that's almost always the first hard disk in your computer.
Note: make sure there's nothing important on your SD card as the above command will wipe ALL data on it.
This guide will show you how to install XBMC with XBian installer for windows, there are others for Mac and Linux.
1st download the XBian installer and extract it to a directory, when done insert your SD card into your computer.
Next run the installer you extracted earlier, when the installer shows itself select XBian 1.0 Beta 1 for version.
Next select your SD card from the dropdown list.
When thats done the Install button at the bottom should become active, when it does click on install and follow any instructions when prompted.
Now the install is finished, you can now configure to your tastes and start downloading add-ons.