Do you know how to create tables and insert/update in mysql?
Basically what you'd do is create a table to hold the results of the form submissions. By default, when the visitor hits submit, you could have a field in the database called approved with a value of no. Write the rest of their submission to the database using insert(), then display it on the page in a form with the values already placed in the text fields. Then make an approve checkbox. If you're going to be updating the fields, use update() . If you checked the approve checkbox, the value in the database is updated from no to yes. Then on your site, to display the approved comments, you'd select everything from the database that had a value of yes in that approved field:
$query = mysql_query("SELECT * FROM yourtable WHERE approved='yes'");
Does this make any sense or have you not done much (or any) work with mysql? Post back if you need more help.
Cgraz