Depending on which version of Producer, you may have DPro and Rapture. Both have quite a few organ programs you may like. DPro expansion pack 1 includes a virtual B3. The programs are located in Expansion Pack 1 > Organs > Virtual B3. Here is a image detailing the features available in the virtual B3 programs

Thanks, I have Dimension Pro and Rapture.

Greybeard, I have about 7 Hammond plugins, including B-5 (in the UVI Workstation).  And as I said before, it really does sound good.  Just another flavor of the "Hammond sound" available through all the various Hammond emulators out there (which really isn't a single, specific sound to begin with, if you take into account all the different tonewheel sets, models, physical condition of all the parts, that Hammond produced over the years).
I'll have to check out the PSP B-Scanner, thanks for the recommendation.  However I do think Blue3 does a pretty good job at emulating the Leslie speaker.  (But as I've found, you can never tell unless you do side-by-side comparisons)

In my latest project I've combined the VB-3 and Blue3 plugins, played and mixed them together to create a composite tone, getting the best of both plugins into a single sound.  I've even matched up the rotary speaker speeds, so they stay pretty much in sync.   By combining the two, I still can get that strong, deep bass when playing a gliss, from the bottom keys to the top, while adding the bright tones of Blue3.

I thought VB-3 was the ultimate sounding Hammond emulator, but it's not until you play them side-by-side that you can really hear the differences.  VB3 almost sounded a bit muddy or muted on the high end compared to Blue3.
So by combining the two plugins, I have a Hammond B3 sound that will cut through all the other instruments (when I want it to), when playing with a full band's worth of instruments.

One more tip I learned during all my research.  When playing around with Blue3, it's worth experimenting with the many different tonewheel sets (including the waxed and recapped ones), also in my opinion the "custom" speaker option sounds best out of all the available speakers in the plugin.  So many choices, it takes days just experimenting with all the various combinations.

Greybeard
 I'm also a fan of L'otary.  To go with it, PSP have created PSP B-Scanner, a terrific plug that emulates a Hammond B-3's vibrato and chorus functions, often a weak point in Hammond VST's.

I'm pretty sure I already own L'otary, but never really use it.  So what's the differences (if any) between the L'otary and B-Scanner?  They look like they both emulate a rotary speaker.   Is the B-Scanner an updated version of L'otary, or does it have additional functions?
Thanks!
EDIT: Oh, never mind, I figured it out, L'otary is a Leslie speaker emulator, while B-Scanner emulates the vibrato and chorus features found within the Hammond Organ itself.

I wish GSI would sell in VST format the upgraded version of VB3 they include in their superb Mojo and Gemini keyboard hardware.  Their VST currently on the market--VB3 version 1.4--is getting long in the tooth.  Blue3 sounds at least as good (better, to my old ears) and, as previously noted, is far more tweakable.  It also has the best user interface, IMHO.  As for B-5 version 2, it's sampled rather than modeled like VB3 and Blue3, which may explain why old fart Hammond players give it the nod in the sonic verisimilitude derby.  It's also on sale right now, I think.  The L'otary and B-Scanner plugs go beyond Hammond verisimilitude and are cool effects to play with in other contexts.
 
If you're burying a B3 in your mix as a pad or an accent, any one of these three VST's will do the job.  If you're exposing it as a foreground lead instrument, Blue3 or B-5 V2 will shine.   

I haven't played a real tonewheel B3 very often but when I saw Dr Lonnie Smith it sure had booming bass. Although I suppose "realism" is overrated these days - almost nobody using the plugin has extensive experience with a real B so what ultimately matters is that it's inspiring to play and sounds good in a mix.

The main thing that stays with me from my years performing and recording with former Mott keyboard player Verden Allen is the strain of shifting his flightcased split C3 and twin Leslie cabs around. On more than one occasion we found ourselves jammed between the organ and the wall of a narrow passage or stairway, it still makes me shudder.
 
I'd have been delighted to carry the VST version :-)

Be wary of simple tremolos which do not have the Doppler effect of a true Leslie.  The Leslie sound is really very complex.  I'd go with Craig's recommendation.

As been mentioned, PSP L'otary is very good but so is Melda's MVintageRotary plug.  I have both of them and they are both EXCELLENT albeit PSPs allow more custom settings.  I stay away from the built in Leslie effects inside of VSTi organ instruments in that they really aren't that good and with a dedicated VST effect, you can use it on any audio track.
 
The reason I have both is that they actually sound different enough that depending on the mix, one will fit better than the other.  Again, I highly recommend either one.  Another great thing about having a standalone LESLIE Vst is that you can use it on any track (leslie effect on vocals, leslie effect on guitar tracks, etc.).
 
The MELDA one goes on sale about once a year for 50% off.  I have not seen the PSP version on any significant sale.  If I could only have one of these VSTs, I would go with the PSP version but like I said, both are very useable.
 
I started a thread about this in 2015 in the software section of the forum if you want some more info about these Leslie VSTs.

I never really had a big issue with VB3 and I'm pretty sure you can use it as Leslie on any audio track. I would honestly expect that to go for most organ plugins. I'm not opposed to separate Leslie plugs per se, I actually have a Ventilator 1 and a Ventilator 2, I'm just suprised to hear people feel the Leslie in VB3 isn't good or don't know you can use it as an FX processor.