What to do when flush() doesn't?

Hi all: I am trying to get information from a rather long-running PHP script to send out messages to the client as things are being processed. In reading the manual, it seemed that using flush() was the ideal command for this. Well, it doesn't seem to be working for me. I've even tried sending over a large number of blanks (like 4096 of 'em) before doing anything, but still no go. The flush() activity is supposed to occur on a page that has POSTed back to itself, so perhaps that's causing the heartburn? Any suggestions on how I can accomplish this type of user mollification? Thanks, Jon