To add scrollbars, use the Tk::Scrolled. For example, you can create a top scrolled frame:

#!/usr/bin/perl
use warnings;
use strict;

use Tk;

my $mw = 'MainWindow'->new;

my @array = map join('=', int rand 100), 1 .. 100;
my $top = $mw->Scrolled('Frame', -scrollbars => 'e')->pack;

my $x = 0;
for my $pair (@array) {
    my ($name, $value) = split /=/, $pair;
    my $frame = $top->Frame->pack;
    my $label_index = $frame->Label(-text   => $x,
                                    -width  => 10,
                                    -relief => 'groove')
        ->pack(-side => 'left');
    my $label_name = $frame->Label(-text   => $name,
                                   -width  => 30,
                                   -relief => 'groove')
        ->pack(-side => 'left');
    my $label_value = $frame->Label(-text   => $value,
                                    -width  => 25,
                                    -relief => 'groove')
        ->pack(-side => 'left');
    my $label_description = $frame->Entry(-text  =>'description',
                                          -width => 30,
                                          -relief =>'groove')
        ->pack(-side=>'left');
    ++$x;
}

MainLoop();
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Note that my example is runable as is, while yours isn't (I had to guess the format of the array values, etc.) Also, adding a space here or there improves readability.

The first argument of split is a regex or a space. Also, I prefer single quotes for strings that don't interpolate anything, and no quotes for strings that only interpolate a single variable.

Update: The array is populated wrongly. See Lotus1's reply for a fix.