Nothing useful yet, just a bunch of links for reference
http://www.victorland.com/slimp3/
http://search.cpan.org/~cook/Device-SerialPort-0.22/SerialPort.pm
http://www.matrixlist.com/pipermail/pgrm101/2003-September/001563.html
http://www.rocketaware.com/perl/perlfaq8/How_do_I_read_and_write_the_seri.htm
http://hamjudo.com/rcx/talkrcx.txt