Created a .eof-poprc file somewhere. It should look like this:
maildir=/home/alice/fmail
mailbox=mail/alice
username=alice
password=secret
All of the values should be changed to reflect your actual situation, of course.
Add the following to your .freenetrc file:
services.pop.class=eof.pop.PopHandlerServlet
services.pop.port=1110
services.pop.config=/home/alice/.eof-poprc
Change the config parameter to point to the actual location of your config file. If you want to use Freenet as the primary POP server for your machine, you can change the port to 110. This would requre you to run your node as root, which seems like a bad idea, generally.
Also, make sure the EOF classes are in your CLASSPATH. You also need Sun's JavaMail and Activation jar files in your CLASSPATH. They're available from java.sun.com.
This depends on your mail reader, of course. Just tell it in the standard way that you have a POP account running on localhost at the specificed port. For a lot of mail readers that would be specified by giving a POP server address of "localhost:1110" for the example setup. Some mail readers may only talk to POP servers on port 110. Such mail readers are dumb.
We have compiled a list of compatible mail readers. Try out your favorite one and let us know.