In Joomla! 1.5, if you simply want to display your component without any modules and without your template styles, all you have to do is add "?tmpl=component" or "&tmpl=component" to the end of the URL, depending on whether or not there are already other parameters on the end of the URL. This trick display the head tag and coponent 

if you want to display the only compnent then in joomla 1.5 add &no_html=1 or ?no_html=1 to the end of the url.

For example, if you just want to view the component on the home page of the new community.joomla.org site, you simply add "?tmpl=component" to the URL like this: http://community.joomla.org/?tmpl=component.

This trick is really useful for template designers because you can isolate the HTML used in a specific component, so you can determine how best to set up your CSS for styling that component.

Enjoy!