See also: Joomla! Extensions Defined
Our template development documentation contains many articles, FAQs and tutorials. A first step to developing a template is understanding how templates are executed.
For more developer information, see Template Development.
Front-end templates change the way your site looks to average users. Most of the templates you use will be Front-end Templates. Three Front-end templates come preinstalled with Joomla!: rhuk_milkyway, beez and Ja_purity.
Back-end Templates are much rarer than Frontend Templates. You will probably never need to change your Back-end Template. Back-end Templates allow you to change the way the administrator interface looks.
There are some wonderful templates that were made in the template contest. There are also many websites where both free and non-free Joomla! templates can be downloaded.
If you are interested in creating your own template than there are a few thing that you might want to know before you start. first you will need to know CSS, HTML, and PHP. Joomla! has created a tutorial for those who would like to create their own template.