Here is a professional guide for GAE developers from Techtarget.com
Developers have a wide range of platforms to choose from in creating cloud-based applications. Two of the most popular platforms are Amazon's Elastic Compute Cloud (EC2) and the Google App Engine (GAE). In addition there are a wide variety of other platforms that have not gotten as much press, but are making traction such as SaleForce.com environment. In this guide, we will dive into some of the more interesting sites with development resources and tips to get the developer rolling.
Google App Engine
Google App Engine is in a preview release.
It is more oriented to testing out the concept and the tools than building mission critical applications. Google is currently giving developers sample accounts with 500 megabytes of storage, 200 megacycles of CPU per day, and 10 gigabytes of bandwidth per day. This should allow most applications to serve about 5 million pageviews per month. In the future, Google plans to keep the basic accounts for free, while charging for additional resources. For complete details see the original post
