Can I edit content on an FTP server through Finder? Is there any way around the read-only access that Finder strictly allows so I can get write access to a FTP server through Finder?
You can use MacFusion, which allows to connect to a FTP server through a filesystem device.
MacFusion requires MacFUSE, or OSXFUSE with the compatibility layer for MacFUSE.


  
  Mount files and documents as a "Volume" in the Mac OS X Finder.
  Work with your files using your favorite Mac OS X applications directly. No manual upload or download needed!
  Support for SSH (Secure Shell) and FTP (File Transfer Protocol) servers.
  Uses your machine's native configuration for SSH, including support for private keys and custom settings.
  Quickly connect to a any server using the Quick Connect dialog, accessible from Macfusion's optional menu item.