Is this the new Google App that will revolutionize the way programs are made and open programming up to a wider audience? Well, that remains to be seen, but it's certainly an interesting innovation. Google App Engine allows you to build web applications on the same huge scale as most other Google applications. It's basically a fully integrated application environment that's aimed at those that want to reach millions of users in the same way as Google products such as Google Apps and Google Reader have.
This is a PREVIEW RELEASE of Google App Engine. For now, account registrations are limited to the first 10,000 developers, and applications are restricted to the free account limits. On the positive side, it's totally free to get started (like all good Google products) and you'll receive 500MB of free space and enough processing power for 5 million monthly page views. However, you'll obviously need programming knowledge to get your app up and running, and in addition, you'll have to be quick as testing is limited to the first 10,000 users.
This is an exciting attempt by Google to take a more determined step towards Web 2.0 than Google Gears, but it remains to be seen if it can deliver on its potential.