It looks like Google is rolling out a second set of invites to Google Wave users. When logging in, users that have burnt through their initial five invites are finding that they've now been granted an additional twelve to dole out to whoever they like.

The invites for the service are in hot demand. The first lot were issued at the end of September, and many people quickly exhausted them. A new set will be welcomed by those who didn't manage to get in on the action then. What's not clear is if the new invites are part of the original 100,000 promised, or an expansion of that number.

Since Wave launched it's appeared on mobile devices, had movies retold inside it, and been granted a Mac-based desktop client. The service has been labelled as difficult to grasp, but the other day we discussed five useful things that you can do with Google Wave right now.

Have you got an invite? What do you think of Wave? Let us know in the comments.