1) Download bindex.jar library from herehttp://sourceforge.net/p/genoviz/code/HEAD/tree/trunk/ext/bindex.jar
2) Create a folder (eg. bundles) and place all jar inside it that you would like to distribute as a plugin.
3) Run following command java -cp /bindex.jar -jar bindex.jar -n IGB -q -r repository.xml
e.g. If your bindex.jar and bundles are both located in folder named plugins then you could type something like following
java -cp /Users/auser/plugins/bindex.jar -jar bindex.jar -n IGB -q -r repository.xml /Users/auser/plugins/bundles
This would create a repository.xml file in plugins folder.
4) You can then use that path as repository location. To use it as repository in IGB, Open IGB >> Open File Menu >> Select Preferences >> Go To Repository Tab and add your path as repository. >> Close the preference window.
5) Go to main IGB window, there you would see a Plugin tab at very right end. If your repository was successfully added then it should show your plugin there. You can select your plugin from there and install it.