There are a few critical items that you must consider that go along with choosing the processor.
a. The Camera: What size imager are you planning to use? Will it be color or grey scale?
b. Response time: What type of response time will your users/customers expect? In other words, do you have 1 second to decode?
or do you only have a few hundred milliseconds?
In general, for decoding a VGA Image (640x480), you may be able to get away with a 200 MHz processor, if you have 500ms or so.
If you move into the 1.3 MPixel range for your imager, we wouldnt recommend anything less than 400 Mhz.
Regarding the trial software, we require a Software License Agreement (and committment) prior to porting our code to an embedded application.
We do supply a Windows-based trial version that lets you decode bar codes found in images.