We will operate from Dubai or India. Want to have US phone number for customer support. How can we have a US toll free number or an ordinary US number? So that we can talk from Dubai or India.

Is there any website or software available for it and with very good features like voicemail etc.?

Skype Offers such services but I am not really sure about the Toll Free Numbers.
http://www.tollfreeforwarding.com Looks good for buying toll free numbers.

I have used http://www.kall8.com for years very good service.

If you have 'vonage' in your area, try them out. They're not available worldwide, but they might be an option. They can easily throw a US number up, as long as the routing is there.

I use kall8, too. No problems to report.

You might also check out: www.vitelity.net
They are pretty inexpensive. And you can route the calls to your office via SIP or IAX. You can connect via a PBX system like Asterisk, or you can use a softphone like XtenLite.

Go with Kall8

Kall8 is good :)

I'd recommend 800pbx. I've used them for a long time now. It's great! I actually canceled a while back, and i'm re-signing up today :D.

We will operate from Dubai or India. Want to have US phone number for customer support. How can we have a US toll free number or an ordinary US number? So that we can talk from Dubai or India.

Is there any website or software available for it and with very good features like voicemail etc.?
If you want something that's just for U.S. communication, you can't get a better deal than MagicJack (http://www.magicjack.com).

Maybe http://www.freedigits.com/ ?

Greetings.