It is designed to replace "batch adding" such that it doesn't require you to babysit the batch add process and you can throttle the adds so that you don't invite your ISP to waggle thier no-no finger at you.
You can find more information about it on cpg-contrib.org
http://cpg-contrib.org/board/index.php?topic=123.0
The new version is downloadable from sourceforge, check the link above for more information.
It will also be available via CVS.
Please keep the discusions of CPGMassImport on the cpg-contrib forums