Some time ago I received an Invitation to join Google Wave. I was so happy as I was looking forward to it since the first time I saw the Google video introducing Google Wave.

For my frustration there was no Wave in there for me to send invitations and start building my group of friends. What a disappointment.

Doing some research on why I couldn't invite I discovered that only people receiving invitations directly from Google are able to invite. If you receive an invitation from a friend you can't invite anyone. (at least for now)

So, what is the use of it then? How can I test it?

Well, I just found the solution... Public Waves.

If you have Google Wave you just need to type "with:public" in the Wave search box and you will see all the public Waves...and there are loads. (with new ones appearing every second)

You can also define the kind of public Wave you are looking for by adding more words to your search: "with:public music"

Once you search for public waves you will find that waves in different languages will be displayed, you can add "lang:en" to filter the languages. (Thanks for adding this Andy)

Andy also suggested (as you can see in the comments) a couple of website for you to check some extra bits and pieces about Google Wave.

http://completewaveguide.com/

http://lifehacker.com/5376138/google-wave-101

Hope this is of any help. (it was for me)