Download the AndFlmsg apk file from the website at:

http://www.w1hkj.com/vk2eta/

And save it to the SD card, either from within the phone or on a PC to
 which the Android device is connected to and has the USB driver
 installed for that device to allow access to the SD card content from
 the PC.

From there use a file explorer to install the .apk file, or on some
 devices use the notification of the completed download to install.

You have to allow non-Android market application to be installed for
 this to work. This is found under Settings / Security / 
 Unknown Sources OR Setting / Applications / Unknown Sources, for 
 older versions of Android.

You will be asked to accept a series of permissions that are explained
 below:

a.  Your location: to provide GPS location for Picture forms or provide
 accurate time when out of cellular range (available but not displayed yet).
b.  Storage: Read and write to the SD card. For storing and accessing
 the working files under the "NBEMS.files" directory.
c.  Your Personnal Information (log data): to allow reporting of the 
 context of an error in case of an application crash (the user can 
 decide to send or not the information after reviewing it).
d.   Network Communication as in Bluetooth and Full Internet access:
 to allow connection to the Bluetooth handsfree kits or headsets used 
 as audio interfaces AND to share / Forward messages over the internet.
e.   Phone calls (as in reading phone status): to disconnect the 
 Bluetooth interface when AndFlmsg's audio is running through the 
 Bluetooth interface  AND a phone call comes in. This is to prevent the
 call's audio from going to the radio.
f.   Hardware controls (audio settings and recording): required for
 receiving and transmitting sound. 
g.   Bluetooth administration: to redirect the sound via a Bluetooth
 interface. 

In your applications list you should now have an Flmsg logo called
 AndFlmsg.