http://www.nubivsti.org/

LITERAL:
NuBi is a free Tonewheel Organ VSTi for Windows. v0.9.3 beta has just been released.

Features:
» Three full manuals – 9 drawbars on each.
» Two percussion voices per manual with 3 mode algorithms.
» Selectable Foldback Frequency < Off / 12K / 10K 6K >.
» Saturation.
» Rotary Chorus.
» 4 tuning modes.
» Works with most PC-based VST hosts.