PostNuke*Cool Site* - The Postnuke Content Management System offers full CSS support and HTML 4.01 transitional compliance throughout. The system is composed of an advanced blocks system, a powerful theme system, modular design and is designed for multi-lingual support. Site also offers official support and communication forums [Official].
DynaWerx Themes and Plugins - Collection of free plugins and themes created exclusively for use with PostNuke's Xanthia Template Engine. Many of the themes are compliant with web standards such as XHTML 1.0 Strict, CSS and Section 508. [Open Source, GPL]
KM4Dev - Community of international development practitioners who are interested in knowledge management and knowledge sharing issues and approaches, and who seek to share ideas and experiences in this domain. The service includes a website and mailing list to facilitate the discussions.
Maximum Development - Project that is working toward integration of Postnuke/eNvolution/Oscommerce for managing E-Commerce, E-Learning, intranet, Workflow, ERP, hotels admin [Open Source, GPL].
PostNuke Community - Official PostNuke support website that contains the most up to date information about the project while providing a central place for help and support for the PostNuke CMS.
Test Drive Postnuke - Provides a demo version of functionality including administrative privileges.