I have used voice recognition with middle and high school students.  It is
a little tricky, my experience with using the digital recorder with the
program is more tricky than just speaking directly into the Dragon
NaturallySpeaking program on your computer and it is a very good thing to
learn and practice the program before you move onto the digital recorder.
You would definitely want to train a voice file for better accuracy, there
are always some errors and depending on voice quality sometimes more than
others. Scan Soft www.scansoft.com just released v.8, supposedly even
easier to train 5-10 minutes and even better accuracy and you are suppose
to be able to use it with more than just their Dragon Naturally Mobile
recorder, you can use your handhelds and other recorders.  I have not
tried this yet.  It used to be required that you train a separate voice
file for the voice recorder which took more like 20 min.  the new v.8 may
have improved this also.  Also it works best with a headset microphone so
the voice quality remains consistent.  Newer versions of Microsoft office
also have voice recognition, not as good as Dragon and does not work with
a digital recorder but you  may have and would be able to play with it.
Cindy