i have an invite in my inbox but I don't know what this is. Please explain?
Did you receive an invite from someone else, or do you have invites to give away?
Google Wave is Google's attempt to replace twitter, facebook, email, instant messaging, irc chat, and collaborative software all with a single web based program.(It's supposed to a better way to communicate with people) It's in beta right now and is pretty buggy and slow, but the concept is cool.
Here is an 8 minute video explaining it:
http://www.youtube.com/watch?v=p6pgxLaDdQw
And if you're really interested, have a lot of free time, or are just bored, here's an extremely long video explaining everything indepth:
http://www.youtube.com/watch?v=v_UyVmITiYQ