This project has moved to <http://christianserving.org/project/truepreview>. TruePreview is a plugin for Apple's Mail.app that allows you to truly preview messages.
As a prospective user, I question the decision to pull such a well regarded plugin off of SourceForge, and onto a self-hosted-self-managed site... Whether the intentions were clear from the get go, the project has since gone offline, and is no longer available. UGH!
truepreview works great
no trouble to install and run, works nicely.