Here are the primary goals of the Trinity project, which is the name of the fork:
"This project aims to keep the KDE3.5 computing style alive, as well as polish off any rough edges that were present as of KDE 3.5.10. Along the way, new useful features will be added to keep the environment up-to-date.
Towards that end, significant new enhancements have already been made in areas such as display control, network connectivity, authentication, and much more!"
Interested persons looking to help can get involved via the project's homepage and also there is a donation link for those who wish to support this project financially.
It will be interesting to see if and how this project takes off. Those people complaining about where KDE 4.x is heading (you know who you are) should be pleased with the announcement.