Has anyone used the App 'Viber' in Europe?

Yes, I have, It worked very well.

I use an app called HeyWire. You can text for free over wifi without your recipient having to have the same app.

I heard about viber this weekend from my sister-in-law who has a viber account for her iphone. I signed up for viber for my android tablet this afternoon. I just called my sister-in-law using viber and it worked great (android tablet to iphone - great voice quality). This will be a good method of communication should a family emergency arise either here in the US or abroad.

Viber and Skype are similar and used by me, although Skype is first choice.

I use an app called WhatsApp- I believe it was free (or $1) and is just like text messaging, but free. It does require wifi however. I use it with my friends in England but I'm sure it can be used with anyone in Europe/worldwide.

As you can tell already, there are lots of apps that basically do the same thing. I use KakaoTalk everywhere (US, Canada, Caribbean, Europe, Asia). In addition to free texting and calling, it supports video clips, photos, voice clips, URL links, etc. Emoticons are fun! You can chat 1 on 1 or in groups. It’s available for iPhone, Android, Blackberry, and pretty much every other OS. As previously mentioned, most of these apps are all free when on Wi-Fi. When on 3G/4G, they are using your plan time. I use Skype everywhere as well...depends on what my needs are at the time.

Thanks a lot. I didn't realize that there were many options .To add to that, there is also FaceTime with an Apple Device. As long as I have my phone setting to have my wifi on.