For free, you can't beat this B3 emulator, and the leslie rotor speed responds to mod wheel, like it should. You have to love developers like Mr. Taips.
The presets, though not many, span plenty of sonic territory and give a great launching point for your own presets. The leslie is believable and very adjustable, including belt tension!!. The 'Mr. Valve' overdrive works to put some or alot of dirt in the sound like you want it to.
Overall, the sounds sit nicely in a mix and sound much better than sampled B3 organs. You owe it to yourself to give this a download and a trial on your own. It's my favorite B3 emulator for free/shareware.
I use it in Tracktion 2 with no problems.
Documentation comes in the form of a .pdf manual, which is pretty complete. It details all of the automatable parameters with AZR3. It also includes the GNU license for the plugin.
Rumpelrausch provides it for free, but asks if you end up using it that you donate to a charitable Non-Government Organzation - cool idea.