Top-of-Page Formats are meant for hardcopy devices, but you can achieve the results you want with a simple hack: make $= equal to the number of lines you are about to print plus 2 for the numbers of lines in INDEXFILE_TOP. Here is an example:

use strict;
my ($prog,$desc,$pages,$date,$file);

my @line1 = (
   qq|prog desc pages data file\n|,
   qq|foo blah 5 bar foo.txt\n|,
   qq|bar blah 5 baz bar.txt\n|,
   qq|baz blah 5 qux baz.txt\n|,
);

my @line2 = (
   qq|prog desc pages data file\n|,
   qq|foo blah 5 bar foo.txt\n|,
);

$~ = 'INDEXFILE';

write_2_file(@line1);
write_2_file(@line2);

sub write_2_file {
   $= = 2 + @_;
   for (@_) {
      chomp;
      ($prog,$desc,$pages,$date,$file) = split;
      write; # to STDOUT for this example
   }
}

format INDEXFILE_TOP =
Program Description       Pages Date Filename
------------------------------------------------
.
 
format INDEXFILE =
@<<<<< @<<<<<<<<<<<<<<<<<< @<<<<< @<<<<< @<<<<<<<<<<<
$prog, $desc, $pages, $date, $file
.
[download]

UPDATE: Doh! Looks like rinceWind has a much cleaner answer.

Change '$= = 2 + @_' to '$- = 0' in the above example for a more robust subroutine. rinceWind++

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)