All front-end text is controlled via Joomla Language files. If you wish to edit the text of any of the front-end templates, check your help file at the very bottom for the most up-to-date location of your language file.
Typically they will be found in one of the following locations:
If you are using Joomla 3.x you can also use the Joomla! Language Overrides Feature in the Admin area as well.