Registering .US domain name..

[firebladeiii]

Is it legally allowed to register .us domain name any one not related to US at all?

 

[Qc4]

Nope, you need to meet the requirements listed here: http://www.nic.us/policies/nexus_requirement.html

 

[Night club]

Visit the registration.us domains with its required and get a suitable domains name.
</www.GoDaddy.com/>

 

[firebladeiii]

What if am I planning a business related to US market? Do I need any legal document to own it?

 

[mrjohn]

You must either be incorporated in the US or have a physical presence in the US.

So, yes, you're going to need documentation proving that your business has a US presence.