Dev wordpress from live wordpress

Hi – I wanted to know how you guys manage your wordpress installations… i have this issue:

I currently have a live site running Joomla… I have wordpress installed on a sub-domain and I’ve successfully managed to import all the blog posts from my live site that runs Joomla to the new wordpress installed in my sub-domain. Now – without much interruptions to the live site – I was to delete all of Joomla and move the wordpress installed and configured in my sub-domain to the live domain.

How is this possible? Any help on this topic would be much appreciated. Thanks.