Tracking what has been changed

Here's the scenario... I am building a site in which users will be able to create and then later edit personal information. When they edit their information, I need to keep track of what was changed so that I can inform via email a person to approve the changes. Here's the flow I'm considering... When an UPDATE page is loaded, I build an array like... $fields = array("table.field1" => value, "table.field2" => value, "table.field3" => value) I then plan to save this array to a SESSION variable. Then, when the form is posted I save the new form contents to another SESSION variable. Then I compare the two arrays and save the names of the fields changed to an array saved in a third SESSION variable. Finally, when I build the email, I can parse the changed fields array to inform the person who must approve the changes. First, does anyone have a suggestion of a better way to do this? Second, I can't seem to save an array to a SESSION variable. I build the array in a local variable and then set the SESSION variable equal to it. When I recall the SESSION varialbe, it's contents is "Array". Then, when I print_r() the SESSION variable, I still get "Array" as the contents. What's up? Thanx in advance for any help. -- Robb Kerr Digital IGUANA