Technbolts-mail is a project mainly written in Scala, it's free.
Simple scala Pop3 and Smtp servers
Install Java, Simple Build Tool, and Git
Clone this repository with: git clone git://github.com/liftweb/lift_sbt_prototype.git
Then cd into lift_sbt_prototype and type: sbt
At the sbt prompt, type: update
Then: jetty-run
Point your browser to: http://localhost:8080/
Voila a running Lift app