I wrote last week on using Objectify-Appengine to decrease the Google AppEngine request loading time. I did not mention my development setup so I'll do that now, hopefully saving you some time:

Start by building a JAR file from the latest source:
svn checkout http://objectify-appengine.googlecode.com/svn/trunk/ objectify-appengine-read-only
cd objectify-appengine-read-only
You should now have a JAR file in target/objectify-508.jar (build number may be different for you). I use IntelliJ and after setting up a fresh AppEngine project, I copy in the generated Objectify JAR file and delete some of the generated JAR files so I have the following JAR files in web/WEB-INF/lib:
This is all you need. You can then follow the examples in the Objectify Wiki. You should re-think your data modeling, away from a relational database mindset. The AppEngine data store may seem limiting from a programming perspective but its scalability and performance advantages make the learning curve very worthwhile.