hi im newbie at site building and im hearing a lot about joomla so what is it and how can i use it thinks
Joomla is a Content Management System. CMS's are used for, you guessed it, managing content. Basically, you install Joomla and you can add categories and content items and customize everything to how you need. You can install different themes to use with Joomla and many different extensions (free and commercial) are available to use with.
http://joomla.org/ It's an open source (free) CMS (content management system). EDIT: garrettheel beat me.