PHP Script to remove attachments from emails and store them on the server

Hi all I have a script that is currently running on my server which intercepts messages being sent into a specific address, it is piped to this through an alias in the aliases file. What would I need to add to this script in order for it to firstly check for the presence of attachments to any email message and secondly if any are detected how can these be saved to disk locally on the server that this is running on Thanks Simon