Frost is a Freenet client program, based on a friendly skinnable GUI. It is capable of file uploads and downloads, searching for files, and has message boards (!) A truly novel application.
It works somewhat like the "Freenet version" of Freegle, except that it is a stand-alone Java application, not an applet. In other words, Frost has a single keyindex that people using Freenet share and query. It is not a standard Freenet keyindex, though - it is stored as a file that is compressed and also includes file metainformation.
The message boards use system called Text over Freenet (TOF).
Home page: http://jtcfrost.sourceforge.net/