Run a script apart from request

Hi all, I am developing a program that does some intensive data processing, and is triggered from a page hit and/or a SOAP request. The processing takes on average 30 seconds to 1 minute, which is OK for a web page (I can use set_time_limit(0) and just display a pseudo-progress bar animated gif and a "Please wait..." message) but I can't leave the SOAP request hanging for that long. I need to send a response immediately. What I really need to do is acknowledge the client that their request has been received and will be processed, and terminate that request... and THEN begin the processing. One way I thought of doing it would be to put the requests into the database and run a cron job every X minutes, but I would like to avoid this if at all possible. Someone had suggested pcntl_fork() but I'm not sure if that will accomplish what I need it to... if I fork(), then send a response, kill the parent and let the child run the process, will the HTTP request wait for the child or will it die with the parent (like I want it to) ? Any advice is much appreciated. Thx, Brad