Google is today sending out Google Wave beta invites.

If you registered your interest back when Wave was announced, you may already have a Wave invite in your in-box.

If you didn't register, or you don't receive an invite, then you should track down someone who did: just like when Gmail first launched, those on the programme will have a limited number of invites that they can send out to friends.

It's likely that sites will spring up offering to share Wave invites, so don't pay the scalpers who are starting to offer them on eBay.

What is Google Wave?

Wave is designed to be a ground-up reinvention of the way we communicate and collaborate. Think instant messaging, but with the open platform potential for plugging in Twitter and other methods of communication, too. (See this video for Google Wave in action on the iPhone.)

For the moment, Google Wave isn't a full public launch but after it was made available to a small number of developers at the Google I/O conference in San Francisco earlier this year, Google is now sending out 100,000 beta invites.

In a conference call with TechRadar in May 2009, Lars Rasmussen, Software Engineering Manager, explained Wave: "It's a communication and collaboration tool we've been working on for a couple of years down in Sydney.

"A Wave is a single shared space where two or more users can exchange real time dialogue, photos, videos, maps and documents in what we call a Wave. Everyone can reply to a Wave, people can come and go and you can drag and drop information from all over the web."

Google wave

PLAY GAMES: You can drag in information from the web and comment as you go

As well as running in a web browser, waves can be embedded in sites, while open source code means that you could even run your own Wave server. "Everything you're [can see in Wave] is an HTML 5 application built with the Google Web Toolkit.

"It does push the limits of the web and it does require a modern browser," adds Lars. It won't work in IE6, but it will work in later versions as well as Google Chrome, Firefox and Safari.

"Later when we show the demo [at May 2009's Google I/O conference] one of the new things we'll add is integration between Google Wave and Twitter which is an example application we hope will inspire developers to build things for real. You build an extension for Wave that users can install, similar to installing extensions for Firefox."

Google wave

ACCEPT OR DECLINE: Meeting request or BBQ invite - you can collaborate with your mates or colleagues on events and chat about them in your Wave

Rasmussen has worked on Google Wave alongside his brother Jens. Both used to work for the mapping startup, Where 2 Technologies, acquired by Google in October 2004 – subsequently the brothers developed Google Maps before moving onto Wave, sparked by their own idea, originally code named Walkabout.

"We were looking at all the advances in technology that have occurred since email was invented over 40 years ago. We looked at how computers have improved dramatically and the many types of communication [that has come about] since then," explains Lars.

Google wave

CHAT AND SHARE: Look at pictures, then talk about them - you can drop into the conversation at any point

"We tried to come up with a new form of communication, as simple as we could make it, which has functionality spanning as many of these existing tools as we could come up with. We're aiming to rethink what communication might look like if we try and rethink everything from scratch," continues Lars.

"After months holed up in a conference room in the Sydney office, our five-person "startup" team emerged with a prototype. And now, after more than two years of expanding our ideas, our team, and technology, we're very eager (and a little nervous) to return and see what the world might think."

Google wave

EDIT CONCURRENTLY: You'll see updates appear letter-by-letter, while you can see everything happen in realtime