Generally:

./configure
./make
./make install
cd $KDEDIR/bin

Depending on the setting of your modem device, you will have to do

chmod +s kvoice

in order to be able to use kvoice as a normal user.
If kvoice is running suid, you will have to configure kvoice (in menu
options->setup) as root.

kvoice is so far only tested on a linux box. So don't expect it
to run on other machines. 

Have fun

Lars Knoll
<knoll@mpi-hd.mpg.de>
