If you follow (if you don’t then you must) Steven Chan’s blog and have seen EBS Technology Stack Roadmap then it is clear that next version of Oracle Apps R12 i.e. 12.2 will come with Fusion Middleware 11g where WebLogic Server replaces 10g Application Server (10.1.2 Forms/Reports and 10.1.3 Web Tier are replaced by 11g Forms/Reports and 11g Web Tier resp.)
If you have not already started with WebLogic Server then here is list of things you should read for a start
1. WebLogic Domain, Admin Server, Managed Server and Cluster here
4. Configure OHS with WebLogic using steps mentioned here
If you need formal training in WebLogic server then check training from Focusthread
Above is list of thing I learned for Weblogic to start with, I would like to hear what other things you think are important to learn in WebLogic (leave them under comments here)
Oracle ACE, Author, Speaker and Founder of K21 Technologies & K21 Academy : Specialising in Design, Implement, and Trainings.