How to handle actions that may take a long time?

Hi there, I'd like to know your opinion about how to handle events that may take more than a minute to finish in PHP. In this case, the code is performing a recursive action on a large LDAP tree where I'd like to present something like a status page ("Please wait, blah blah" with some animated gif or so), while the action takes place in background. Is it possible to fork away this PHP code and set some SESSION vars to trigger the end of the status page? Or do I have to put this action behind a one pixel image and act when the page is "really" complete? Also I'm not sure how to handle the script execution timeout problem... Any ideas/hints? Some feedback would be appreciated ;-) Cheers, Cajus