Tango Video Calling by Sgiggle, Inc. (available free in the App Store) is a video-calling app that’s similar to FaceTime, but has a few more features that gives it a definite edge over Apple’s built-in video calls.

The most notable difference?  Tango works over 3G.  This is often the complaint I hear most about FaceTime.  It’s been promised 3G functionality is coming to FaceTime… someday.  We also heard that about tethering and how long did that take?

So how does it work?

Open the app for the first time and it asks you for your name and number — that’s it.  You don’t have to create a profile or come up with another username and password or post a profile picture.  Name, number, done.

The first menu is your contacts.  But not all your iPhone contacts, only people in your address book who already have Tango installed.  You don’t have to mess with searching for other users through Twitter, Facebook, your phonebook, etc.

There is an invite option however — that’s the 2nd menu.  You can invite by email or SMS, and it already has an invite message prepared (which you can edit).  You just have to select whom to send it to.

The third menu is settings, where you can change your name or number, or check out the tips, which really should be renamed to FAQs for Dummies.  (Example questions: What is Tango?  How can I sign up for Tango?  Is Tango working right now?)

What’s it like in a call?

When you call someone, they’ll get a push notification message asking to Accept or Cancel the request to Tango.  Accept and the call begins, and it’s actually just an audio phone call via VoIP. It’s all data, no minutes used.

You have to tap the video camera icon with the T to enable video.  Once that revs up, it’s exactly like Facetime with a camera swap icon for iPhone 4 users and a mini window for you to see yourself.  My only gripe, which I’m sure will be changed in an update: you can’t drag the mini window around to a different corner.

You can tap it though, and it will switch you to full screen and your caller to the mini window.  This is great if you’re vain and want to look at yourself more, especially because your friend won’t even know!

Video quality is decent.  In a call with another iPhone 4 user, it got pretty choppy at times, but this has happened on FaceTime too when using a 3G unrestrictor with poor reception.  Overall, in my limited testing, it’s comparable to FaceTime’s quality.

Why use Tango instead of FaceTime?

If using it over 3G doesn’t sell you, here’s another key feature: you can Tango on the 3GS and with devices running Android.

I tried a video call with a friend who has a HTC Evo running Android.  The call was clear, though he had some problems with the app which didn’t surprise me, because you know, it’s Android.

Unfortunately, weirdly, you can’t tango on the newest iPod Touch.  Hopefully that will change in an update soon.

You can check out a list of all compatible devices here.

So there’s everything you need to know about Tango!

I really like this app so far.  It’s what I wish Skype would hurry up and do, but in the meantime it’s a great alternative to FaceTime.  I’m glad to see video calling is indeed branching out and able to cross platforms and devices, making it more universal.

What do you think? Have you used Tango already, or will you try the app out now?