I am running Windows XP.

Ah, that changes things considerably. You could use the standard Unix, on Windows emulated approach, such as fork. But you can use Windows specific methods, too, such as using Win32::Process. See They didn't give me a fork so I have to eat with a spawn..

As a variaton on that theme, I made a little module that, when used in a program, restarts the script with the same parameters, but without a console:

# Save as module file Win32/Detached.pm, somewhere in @INC
package Win32::Detached;

use strict;
use Win32;
use Win32::Process;
use Cwd;

if(@ARGV and $ARGV[0] eq '-nolaunch') {
    shift;
} elsif(!$^C) {
    Win32::Process::Create(
        my $ProcessObj,
        $^X,
        join(" ", map { tr/ // ? qq["$_"] : $_ } $^X, $0, "-nolaunch",
+ @ARGV),
        0,
        DETACHED_PROCESS,
        cwd,
    ) or die Win32::FormatMessage(Win32::GetLastError());
    exit;
}

1;
[download]

Simply do

use Win32::Detached;
[download]

in your main script, just making sure you don't use "-nolaunch" as a command line switch.

If that module is not handy for you — to be honest, I've rarely ever used it — you can at least borrow the parameters for the API call.

If you want to permanently run a perl script in the background, check out how to run a perl script as a service — for more detailed info, see also this online article.