The answers from JMa & brasofilo are perfectly valid.
But as you state that your question is about internationalization & that the content of the pages will be almost similiar, you may be better of with another solution. It can be quite a nightmare to sync a lot of content between wp multisites.
You should also read the Before You Create A Network page of the Codex. Particularly the "Do you really need a network?" part.
If you plan on creating sites that are strongly interconnected, that
share data, or share users, then a multisite network might not be the
If your websites will have almost identical content and just a few static pages per website are different, you can have a look at the Domain Mapping System plugin. That plugin is able to map domains to static pages.
If you need internationalization on top of this, you might just additionally install qTranslate or WPML.
To sum up:
- If your websites will differ only by theme (layout/menu) and one (or only a few) custom static-pages then you should have a look at the DMS plugin.
- If you want the websites to act like separate wordpress installs use wp multisite.
You could also use a mixture of both solution e.g. multisites with each site having the DMS plugin enabled so visahq.in is a multisite blog and australia.visahq.in is a DMS mapped static page within that multisite blog.
This are just a few hints from me. I think the desired system is way to complex and we don't have the full specification context here to provide a direct solution, but just to show up some possible ways and give some ideas.