First and foremost, you must be aware that the Pharo project only accepts code published under the MIT license. By publishing your code in the SqueakSource Pharo or PharoInbox repositories, you are agreeing to this condition.

This page explains in detail our process
http://code.google.com/p/pharo/wiki/HowToContribute

- report bugs
- join the mailing-list
- fix and commit. See screencast.