What do you do when you have a feature in your Web application that takes longer than a second or two to finish? You need some type of offline processing solution. Check out several methods for offline servicing of long-running jobs in your PHP application.
http://www.ibm.com/developerworks/opensource/library/os-php-batch/
http://www.deshong.net/2007/11/robust-batch-processing-with-php-part-12/
http://brian.deshong.net/talks/2008/phptek/robust_batch_processing_with_php.pdf
