HeyWire, a Boston based startup, offers an incredibly robust social communications hub for users worldwide to tap into its free, mobile SMS network that connects with Twitter, Facebook and Google Talk. HeyWire aims to take on group chat competitors like GroupMe and Fast Society this week in Austin, Texas at SXSWi.

Today, HeyWire announces its latest version of the app, which features an integrated group texting platform. Within the third iteration of HeyWire’s app, a user will be able to group text multiple mobile numbers, people in their Facebook chat or GTalk contacts and simultaneously update their status on Twitter by including “40404.” In fact, HeyWire claims to be the only app that lets users do this. Replies can be individual or to the group. So you can begin communicating one-to-many, receive messages back one-to-one (and keep messaging privately back and forth). The team believes this will be a huge boon to users at this week’s technology and music Conference in Austin, Texas.

HeyWire Group Message 220x330 SXSWi 2011: HeyWire launches group chat with Facebook, Google and TwitterAnd in my opinion, the social connectivity is not even its coolest feature. Yesterday I wrote about HeyWire’s impressive ability to let users text a U.S. number from anywhere in the world, for free. HeyWire assigns each user with with a real phone US +1 number so right away you can use that number, over an Internet connection, to text with anyone in the +1 area code, skirting international fees.

Within the latest app, find other HeyWire friends by location using “HeyLo,” which shows you how far away you are from each other in miles or kilometers. Another smart feature is SmartSMS, which is a text auto-responder that sends replies for you when you’re unplugged. It’s great if you’re driving. When you reach your destination, simply turn SmartSMS off and you can respond to messages.

GTalk is great on the device as long as you don’t keep your GChat on invisible during the work day. Enabling GTalk on HeyWire obviously disables this feature within your Google Mail client. However, if you have Facebook Chat disabled, it will not re-enable it through HeyWire.

The app is supported through in app purchases like theme and ringtone options. You can also buy out the advertising within the app; on a yearly basis it’s $9.99, monthly $3.99. While there’s never an ad within a message, it does run banner ads through iad’s ad network.

Header 220x330 SXSWi 2011: HeyWire launches group chat with Facebook, Google and TwitterUses for group texting apps that have location and social built in at a place like SXSW are endless. Wanna see which friends are at a panel but you didn’t make it out of your hotel bed? Text them from your iPad. At a crowded party and want to bring a few people with you to a VIP gathering? Making dinner plans and want to see who’s in for TexMex and margaritas?

If not all of your friends are on HeyWire, you can upload your contacts so that incoming messages will display your friends’ names instead of his or her mobile numbers. The key to reaching the app’s maximum usefulness is adoption of course. HeyWire is adding 150,000 plus users per month and sending millions of messages per day, globally.

While photo sharing is on the road map, HeyWire’s VP Marketing Glenn Kiladis says phone calls and conference calls will not be the next greatest thing rolling out on HeyWire anytime soon.

“We’re all about connecting people in better ways. When we talk about new features we want to roll out, we ask, are we connecting users in a better way? And then everything we do has a global spin to it.”

-HeyWire’s VP Marketing Glenn Kiladis

The startup launched on September 27th, 2010 and is currently growing by hundreds of thousands users a month. HeyWire ranks consistently in the top 20 social networking apps for iOS on the iPhone, iPod Touch and iPad. They launched their app on Android in January and are one of the only texting apps on Android that includes Facebook chat. Later this month, HeyWire will be implementing other IM services into the app for both platforms.

So which group text messaging app will you choose this week?