How to run multiple websites from single WordPress setup

I want to create a website like visahq.com in WordPress, actually visahq.com has multiple websites like visahq.in for India, visahq.ru(will be shown in Russian) for Russia etc. and each TLD has multiple sub-domains like visahq.in has a sub-domain for Australia http://australia.visahq.in/ like on for each country. Content of all websites are almost same with some changes based on conditions.

My problem is I want to manage all TLD and sub-domains on a single WordPress setup how can I do this with WordPress.

You could set up a multisite installation with sunrise configuration. This would allow you to manage one installation for your multiple domains.

Be sure your hosting is ready for it.