One useful trick for this sort of problem is using the modulus operator, %:

use constant MAX_ITEMS_PER_COLUMN => 25;
my @list = (1..50);
my $numcols = int(@list / MAX_ITEMS_PER_COLUMN);

print "<table><tr>\n";
for(my $i=0;$i<@list;$i++)
{
  print "<td>$list[$i]</td>";
  if ($i % $numcols == ($numcols - 1)) {
    # Start a new row
    print "</tr><tr>\n";
  }
}
print "</tr></table>\n";
[download]