use warnings;
use Date::Manip;
while (<DATA>) {
        if (/(.*: )(.+)/ and defined($d = UnixDate($2, "%c"))) {
                print $1, $d, "\n";
        } else {
                print $_;
        }
}

__DATA__
xmas.com : 08-Nov-2007
-------------------------------------------------------------------------------
jacket.com : 30-Jul-2006.
-------------------------------------------------------------------------------
shows.com : 2006-12-20
-------------------------------------------------------------------------------
item.com : 22-Aug-2009.
-------------------------------------------------------------------------------
...