Its Ugly But It Works(tm)

#!/usr/bin/perl -w

while (<DATA>) {
        $num = join "-", split /\D+/;
        $num =~ s/^-//;
        print "$num\n";
}

__DATA__
(01)1234 5678
(01) 1234 5678
01-1234-5678
01 1234 5678
01 234 4567
[download]

Updated
Not so ugly now...