Yesterday’s announcement that Facebook is buying Whatsapp has got the pundits chattering, and with good reason. But for many users, it could be decision time if they don’t want their messaging connected to their Facebook lives or if they just don’t like Facebook at all.

There are fortunately a fair few options available, including services like Viber, and we’ve been looking at one of the interesting contenders…MTalk.net . The interesting thing about this service is the fact that it’s a) non-proprietary in that it uses the standard open source SIP protocol for the messaging functionality and b) it goes way beyond just offering a neat chat and image sharing app.

The service not only offers Whatsapp type instant chat via SMS for free, but also gives you a permanent web address which you can use to let anyone in the world text or call you for free over the Internet, even if they’re not an MTalk user.

You can also get a free 20 minutes worth of calls and free basic voicemail for registering, plus in Europe either a London or Italian landline number (like a Skype-In number) for free. This means you can make very free landline calls between the two countries, and if you need other countries you can pay an annual €36 registration fee. Similar to Skype in fact.

The end result is within minutes you can be contacted for free by the text of voice chat app on mobile phones, via a click to talk/text button on a web address (e.g. http://erikablau.mtalk.net/), or you can be contacted for free on a London or Italian landline phone number. All run on an open network via SIP protocols.

As with all of these apps (available for Android and iPhone by the way) it’s a matter of how quickly you can get your friends and family to use it, but from a first look we really like the user interface. It’s very simple to understand and you can get going instantly with very little hassle. There are also some really cool advanced settings to help you optimize your audio and tune it to how you like it, which we’ve never seen before in an app like this.

If you’re in the market for a comprehensive and very well thought out messaging app, then you really should check this one out. We’re very impressed indeed.