Learn how to install Joomla! on your own PC to avoid making mistakes with a Live website. Installing in a test environment lets you see what your Joomla! powered website will look and feel like before you even purchase hosting. You can even install VirtueMart on your local computer and test functionality of the extensions like theme, payment gateway, modules etc before you finally upload the same on the live server. 

Read more: http://www.brighthub.com/internet/web-development/articles/12012.aspx#ixzz0YSPfngQf