First, at the beginning of your script (after use strict; :), autoflush your output buffer:

$|++;
[download]

Second, I suggest your output page watches it's HTML. It's easy to create a page that displays a "This page may take 10 seconds to load, please be patient" message at the top, just as long as a TABLE tag is not waiting for the script output to finish rendering.

For an example, go to any slashdot page with 300 comments on it. The banner ad loads quickly, the rest renders when ALL comments have loaded (ie, the TABLE they are in finishes loading).

For longer waits, you might want to look at setting up a child process that whacks output to a static file, with auto-refresh on your 'please wait' page to check status and display when complete. (not 100% on easiest way to do this, ie "forked if I know (sic) ... oh well :)

cLive ;-)