Thought this might interest people.
wow - that could be really useful - thanks for the heads up - cheap too
I’ve been using it for years, its an excellent program. Most dslrs/lenses are in the database for automatic barrel/complex distortion correction, a real time saver.
This looks pretty much exactly like the one already built into photoshop, except it reads exif information. Which doesnt exist on a rendering anyway.
When you need some CA or distortion to make renders more photographic, PTLens is indeed no better than the ps filter.
As peterguthrie says, it strenght is in removing complex distortion from real-life lenses which sometimes have a combination of barrel and pincushioning distortion. Something the Lens Corretion in ps cannot cope with.
I’m using it for a while now and it works great indeed.
The only downside is, it doesn’t integrate with lightroom.. 
The fact that you can buy this standalone for $25 makes it worthwhile for some. If you bought a standalone license of this, PixPlant, CrazyBump, and a decent DSLR with one or two good lenses and then add Gimp to the mix for light retouching, you would have a very capable commercial texture creation toolbox for relatively cheap.