Sony Digital Voice Recorders:
Dragon NaturallySpeaking works with several of the Sony Digital Voice Recorders. Infact they partnered together to offer a "VTP" (Voice to Print) bundle which includes a selected Sony voice recorder and the Dragon NaturallySpeaking Preferred software.  

The Sony Digital Voice Editor software that is packaged with Sony digital voice recorders provides a link to Dragon NaturallySpeaking. The link converts the downloaded recordings to the file format needed to work with Dragon NaturallySpeaking. The software requires a WAV file (suggested 11.25 kHz 16 bit mono) in order to complete transcription.  When you click the Voice Recognition button (ABC Button) in the Sony Editor program, the application automatically converts the file to the proper format and launches Dragon NaturallySpeaking.

Note: WAV is not a preferred recording format with digital recorders because the file size is quite large. File formats that offer better Compression (more record time) are used however the files typically can be converted to WAV once downloaded to the pc.

Olympus and Philips Voice Recorders:
Dragon NaturallySpeaking also supports integration with many of the Olympus and Philips voice recorders. The process is less automated because there is no direct link between the recorder software and Dragon NaturallySpeaking.  The files have to be converted manually.  This is generally accomplished by right clicking on the file and selecting Convert File to WAV. To transcribe the file, launch the Dragon NaturallySpeaking program and click "Transcribe recording" from the Dragon Bar.  Click browse and select the file you would like to transcribe.   

Does it work? What is the overall accuracy?
Accuracy varies depending on the speaker, the device, and the environment.  98% accuracy can be achieved consistently when proper guidelines are followed.  There are limitations,  for example if you are dictating notes in a noisy conference hall and other  people speaking near you, the results will probably be less than desirable.