(Last Updated: December 2013)
Introduction:
The Raspberry Pi is a credit-card sized computer that plugs into your TV or screen and a keyboard. It's a capable little PC which can be used for many of the things that your desktop PC does, like spreadsheets, word-processing and games. It also plays high-definition video. The Raspberry Pi was intended for learning students how to program in Python. The Raspberry Pi can be used to do all sorts of projects ranging from low level embedded electronics up to full blown media centres and everything in between. It can be used to control things at home via the Internet. The endless capabilities and the cheap price tag made it one of the fastest growing development platforms to hit the world.
Hardware Description:
The Raspberry Pi as mentioned is a small credit sized computer. The Raspberry Pi currently comes in two models, model A and model B. Also note that there were more than one revisions of both models, but I am only going to focus on the ones currently available.
Model A is as follow:
(As at April 2013.)
Model B is as follow:
(As at April 2013.)
Quick Start Guide:
Short Version:
  1. Connect Raspberry Pi with SD Card preloaded with a suitable OS to your TV with a HDMI Cable and attach a USB keyboard and mouse.
  2. Power it on
  3. login user name: pi
  4. login password: raspberry
  5. type: startx
  6. The desktop will start and you can work on it like a linux PC.
Full Version:

Follow these instructions OR:

  1. You will need the following items: 5V, 700mA (preferably more) power supply with micro-USB cable, USB keyboard, USB mouse, Screen or TV using HDMI or converter to convert from HDMI to DVI, LAN cable (RJ45) with Internet connection, SD Card, SD card reader.
  2. Download your Linux operating system of choice Linux for Raspberry Pi...
  3. Format your SD Card using SD Formatter for SD/SDHC/SDXC. to FAT32, not FAT16!!
  4. Write your image to the SD card using the SD card reader and the program WinImage. How to use WinImage, A quick WinImage tutorial...
  5. Connect your Raspberry Pi to your display, your mouse and keyboard. Insert your SD card into the Raspberry Pi socket. Connect your power supply and power it on.
  6. It will load all the linux kernel files and stop at a command prompt, enter your username and password. Note that Linux is case sensitive.
  7. Username is usually: pi and password is usually: raspberry
  8. start the desktop by typing startx
Setting up a media centre:
Short Version:

Okay, so here is the short version of how to set up a media centre at home:

  1. Get all hardware. Raspberry Pi Model B, a high speed SD Card, a HDMI cable, a High Definition TV with HDMI input, USB power supply for Raspberry Pi, External Hard drive externally powered with movies on.
  2. Download a media centre image file. Many are available on the Internet, Google is your friend.
  3. Write the image onto the SD Card.
  4. Connect your Raspberry Pi to your TV via a HDMI cable.
  5. Connect a portable harddrive (with external power).
  6. Power everything up and start to use it.
  7. Connect it to the Internet and update your XBMC.
Full Versions:

Or you can follow one of these links to set it up:

01. RaspBMC Raspberry Pi Media centre based on RaspDebian (Debian Linux on Raspberry Pi) and created by Sam Nazarko. I use this one.
02. OpenELEC Open Embedded Linux Entertainment centre build from scratch for multiple Linux platforms by the community.
Notes:
  1. Buy a high quality high speed SD Card for your media centre, it will speed things up a little.
  2. On the Raspberry Pi things tend to be a little slow when used for a media centre, so be patient when operating the media centre.
  3. When your media centre stop responding, you can wait a moment or you can restart the Raspberry Pi by cycling the power.
  4. In the beginning it seems like effort, but you soon realize that you are using your Raspberry Pi media centre more than the other devices.
Add-ons:

Okay so now you have a working media centre and you are connected to the Internet. What is next?

Add-ons! You can download from hundreds of add-ons and believe me, this is worth the effort. everything ranging from audio, video, applications, pictures and many more all including things like I-tunes, weather, programs, Internet TV, animation, books, news, radio, google, facebook, flickr, wallpapers, skins and a whole lot more. Check it out and download your favourite ones.

Here is a selection of what I downloaded:

  1. YouTube by TheCollective. Obviously, to watch YouTube videos.
  2. MyEpisodes by Maxime Hadjinlian. Automatically set watched episodes on MyEpisodes.com.
  3. The Movie Database by Team XBMC. themoviedb.org is a free and open movie database. Everything about movies and it can retrieve metadata to give your movies a better user experience by downloading posters, fanart etc.
  4. The TVDB by Team XBMC. TheTVDB.com is a free and open TV Scrapper. Everything about tv series and full metadata.
  5. TheAudioDb.com for Music Videos by Team XBMC. The name says it all.
  6. Google by Rick Phillips. Search, view and save Google Images.
  7. Facebook Media by Rick Phillips. Browse your and your friends' facebook photos and videos.
  8. CU LRC Lyrics by Taxigps. Shows the lyrics of your MP3 music that are playing. You download the lrc files and save it as teh same filename as your mp3, just with the lrc extension.