Google Wave, the strangely compelling mixture of e-mail and instant messaging that was demonstrated at the Google I/O developer conference in May, will admit a limit number of school and business users this fall, with general availability promised next year."Over the last couple of months, we've been very busy developing the product, opening the protocol and learning from the thousands of developers who are using and contributing to Google Wave," said Google Enterprise's Matthew Glotzbach and Google Wave's Stephanie Hannon in a joint blog post on Tuesday. "While the product, platform and protocols are still being developed, we're extending access to some of the highly collaborative people and communities we hope to benefit in the future - businesses and schools."

By bringing in business and academic users, Google hopes to make sure that wave appeals to the needs to its paying customers as well as its ad-subsidized ones.

Google has posted a sign-up link for Google Apps administrators who want to give wave a try.

If you have the stomach for unfinished software and the time to explore, I recommend taking Wave for a spin. I was impressed by the demo presented at Google I/O and my periodic visits to the developer preview make me wish the product were done so I could start using it outside of the Google sandbox.

I wrote about my impressions of Wave in more depth in an article in June.

Google has done a lot of things right with Wave, in terms of making it an extensible, open-source platform for collaboration. The challenge the company faces is getting people to understand what it can do and why one might want to use it.

It won't replace e-mail, which has been around for over forty years in one form or another, anytime soon. But it's bound to make...um...waves when it's finally released next year.