Developer: PCF (no news … but soon)
Publisher: JoWooD (thx fleabay)
Release: October 26th 2007 Amazon.co.uk and play.com
Platform: PC

I also found 2 german links
GIGA-Games
ingame.de

It will be a new stand alone title.
Not just an simple expansion! Including new content + new playable character and a brandnew story. And its built on the original PK engine.

Keep in mind its PK1.5 and not PK2 wich will be (so god will) built on an entirely new engine and released 2008/2009.