Finally I'm barely free from website setup and can talk about the development tools we will use.
The implementation language will be Java. Java is a language I know best, and we have big load of developers who know Java and will benefit from this project. So to get Java go to
java.sun.com and download JDK and JDK documentation. I recommend to unpack JDK source code which comes with installation, and put URL to documentation onto easy accessible place.
If you want to learn Java - get Thinking in Java by Bruce Eckel - you can download electronic copy for free or better get a printed version. You can download Java Tutorial and place link onto it on your desktop.
I use Eclipse with Webtools.
I use Apache Tomcat 5.5
This seems all on tools we need right now. I will add more on the go.