Something else you may want to consider is to make your script re-entrant using CGI.pm. It's similar to what Joost said.

I'm doing that with a simple shopping cart application now. Since I didn't specify an action in my form, the application calls itself again when the submit button is pressed. I'm using this method to both check to make sure I have data in required fields, and to untaint it as well. The CGI docs have some good examples of this.

HTH!