SimpleBukkit is a java API for bukkit plugin developers.
You need to have Maven installed (http://maven.apache.org). Once installed, simply run in saved directory:
mvn clean package install
Maven will automatically download dependencies for you.
We happily accept contributions. The best way to do this is to fork SimpleBukkit on GitHub, add your changes, and then submit a pull request. We'll look at it and merge it into SimpleBukkit if everything works out.
Your submissions have to be licensed under the GNU General Public License v3.