Good news: Procedural Inc. released a new version of the CityEngine. Even if your trial period has already expired, Procedural added another free trial period (30 days) for the 2008.2 version!
The CityEngine 2008.2 has a faster performance, better memory management and improved user experience. Other specific highlights are: learning videos and full documentation (complete manual); new tutorials available (video or text); export to RenderMan, mental ray and Google Earth (via Collada); import the street network of any existing city (from OpenStreetMap);
Together with the CityEngine 2008.2 release, Procedural introduce a more flexible price model: the CityEngine license retails new for $ 4,950 and the Subscription (updates & support) for $ 1,950. And for a short limited time...