Refer to this
http://www.magentocommerce.com/design_guide/articles/working-with-magento-themes
And your layout and template folders need to be created as
'themename'>layout
'themename'>template
eg:app/design/frontend/default/'themename'/layout
and app/design/frontend/default/'themename'/template
Same goes for the Skin mapping.
Also in magento admin configuration
In Design tab you need to enter the package name as default
as per your config
and in the themes in template, layout and skin(Images/CSS) you need to put your 'themename'
.