I have committed changes to the Tunnelblick source code that implement a launchd daemon instead of using an SUID helper on OS X 10.5 ("Lion") and higher. The changes will be available in the next beta release.
This is such a complex change that I would like extra testing done before I include it in the next beta release. I have created a "snapshot" (pre-release version of Tunnelblick) is available that includes the changes. Email me privately at my Gmail address, jkbullard, for a link to download the snapshot.