[petdog]

Poor man's skype:

sender

    arecord -f cd -c 2 | lame -b128 - - | netcat -u your-ip 6881 | mpg123 -

receiver

   arecord -f cd -c 2 | lame -b128 - - | netcat -u -l 6881 | mpg123 -

[1337p337]

I used to do this with a friend in the days when modems tied up phone lines. You have to pass a much lower number to lame's -b option, though.