Hi Zeno2,
what kind of application are you going to develop - maybe a web application?
First of all you need an evironment (maybe some kind of a shared file server) where all your project files (Java classes, XML configuration files, et cetera) will be stored. In our team we have a good experience using Perforce as a file database for our project. This tool provides several good functionalities like file locking, file history and so on.
Second, you need an installation of JCo for your environment. You can download it
http://service.sap.com/connectors. The installation and configuration of JCo needs to be done manually - as far as I know, there are no installation scripts existing right now. How to intall and configure JCo was descibed in another thread in this forum.
If you develop a web application, I would recommend the Jarta Struts Framework as your web application' s process logic controller. Struts is in short a Java implementation of the MVC paradigma especially designed for web applications. It is quite easy to configure and is very fast and robust. As far as I know we had no real problems with it. You can find Struts here:
http://jakarta.apache.org/struts/index.html. For testing purposes, you need to install a servlet container. I would recommend Tomcat rather than SAP's InQMy since it is robust and fast. A downside of Tomcat is that it quite hard to configure. A big advantage of Tomcat is the very fast remote debugging functionality - you can use the great debugger of Eclipse to debug your web application.
I hope I could have helped you,
regards,
Tim