Heh, beat me to it... just came back to say that I've just discovered the perlfaq and in perlfaq4 found the answer to my troubles using unpack

#!/usr/bin/perl
#converter.plx
use warnings;
use strict;
print "Please input a decimal no. to convert to binary : ";
chomp (my $value = <STDIN>);
$value = unpack("B*", pack("N", $value));
print "$value";
[download]

Thanks for everyone's help and patience, hopefully the perlfaq will provide some answers from hereon in, though it's nice to know there is somewhere to come and ask very basic questions without setting off howls of derisive laughter!