The OpenERP framework not only provides a lot of power but also comes with a fairly steep learning curve. While Chapter 13, Discovering Custom OpenERP Modules will help get you started, if you are serious about developing for OpenERP, you will find the resources listed in this section valuable in your pursuit.
The best thing about this resource is it condenses down the most important details into a single, easily downloadable PDF document. While you won't get a lot of examples or explanations, what you will get is a very good overview of the OpenERP framework, which is also useful for a quick reference. This PDF document is available at https://www.openerp.com/files/memento/OpenERP_Technical_Memento_latest.pdf.
OpenERP keeps a somewhat updated technical developer resource available online. It is also accessible from the main OpenERP website, but you have to dig a bit to get directly to the OpenERP server documentation. This is a must-read resource for expanding your OpenERP development skills. This documentation is available at https://doc.openerp.com/trunk/server/.
Wouldn't it be great if you could try out a variety of OpenERP builds and installations quickly and easily without going through all the time and complexity of an OpenERP installation? Well fortunately, OpenERP Runbot provides you with many different OpenERP branches that you can connect to and use to actually review the build for yourself.
This resource divides the installations by version, build, and age of the version. Even better, you can get immediate access to the branches right on Launchpad. OpenERP Runbot is available at http://runbot.openerp.com/.