Posted for cfi@instructor.net:

 Larry,
 You have a few options.   First, cell phones are the easiest, just get an
 adapter for your headset and it works great.  Text messages work too.
 Just keep in mind that cell phones, or any transmitting devices are not
 leagal when IFR.   Depending on where you are wanting to do this, there
 are repeaters (VHF and UHF) that could be used if they are linked
 together.  In Colorado for example, the Colorado connection works very
 well and you can talk to just about anyone in the state and surrounding
 states just using a hand held 2 meter ham radio.  The HF idea would work
 too, but your 500 mile range will make it very "sun spot" sensitive, and
 during the day you could probably be in the 40meter (7.xxxMhz) band with
 good success, but at night maybe 75meters.  Not a good option unless you
 trail a long wire, which won't slow you down (much).  The best option in
 my opinion is again the amateur radio VHF or UHF bands using the
 internet.  A lot of repeaters are now linked via the internet, so you
 could actualy talk to just about anyone in the world if you know the
 access code to the repeaters.  (a free service, and the access codes are
 easy to find).  WIRES or Echolink systems.  I've been using this for a
 long time and works great even in an airplane.  Of course you will have
 to interconnect the radio with your audio system or headset, and get a
 ham radio license.
 
 Ron Galbraith
 LNCE N5ES
 Amateur Extra Class N0EC