XBMC is a free and open source (GPL) media player and entertainment hub for digital media. XBMC is available for Linux, OSX, and Windows and in more than 30 languages.
To install XBMC on ubuntu 11.10
1.Open Terminal.To open terminal click the Dash home from unity launcher.And type terminal in the search field.And click Terminal
2.Type the below code in terminal and hit enter.
sudo apt-add-repository ppa:nathan-renniewaldock/xbmc-stable
Type your ubuntu password if needed and press enter.
3.Then press enter to continue or ctrl-c to cancel adding the ppa.
4.Type below command and hit enter
sudo apt-get update
5.Then type below command and press enter
sudo apt-get install xbmc
6.After the successful installation,click the Dash home from unity launcher.And type XBMC in the search field.And click XBMC.
