hato-mta is a Mail Transfer Agent with powerful integrated spam detection and filtering capabilities.

hato-fetch is a fetchmail replacement and Swiss-Army knife for managing mail folders.

Documentation of these is available in the manual at

http://synthcode.com/scheme/hato/doc/hato-manual.html

The current development includes many new features and has been ported to Chicken 4.0, leading towards a 0.4 release hopefully in the near future.

Long term goals will be to switch to the chibi-scheme module system (which will likely converge with the upcoming R7RS standard), and to provide converters from that module system to other Scheme module systems, so it will no longer be Chicken specific.