The preview release of Google App Engine is restricted to the first 10,000 developers to sign up.
Not a developer? Let's try another metaphor: Have you seen the Japanese flick "The Host?" Well now you don't have to. Google wants to do the hosting for you. Then you can hire developers to create mutant software apps on the GOOG infrastructure.
If you are a developer, you already missed the latest edition of Google Campfire One, the developer get-together at the Google campus.
(Yes that's the invitation-only S'Mores roast held at the Googleplex, hence the, uh, unique brown Google Campfire logo.)
The bennies of Google App Engine:
1. Write code once and launch.
2. Absorb traffic spikes with automatic replication and load balancing. Think Bigtable.
3. Integrate with other Google services with built-in components and Google's library of APIs for plug-and-play functionality.
Based on Google's aggressive product marketing roadmap, we anticipate Google App Engines to be out of beta no later than 2012.
So cry w00t!!! and let slip the dogs of search engine war games!