The Plone website is the best place to start. Especially useful is the documentation area.

The Zope community website provides information about Plone's underlying application server and CMF, it's content management software

For developers with deeper questions, Plone has Mailing lists , recipe websites and an online chat room that provide assistance from experienced Plone/Zope developers.

If you are a developer and have done something cool or figured out some gnatty bug, please contribute your experiences at the Plone website

Thanks for using our product. The Plone Team