You can grab the data he just inputted from the database and enclose that within an email then send it to him. If you use mysql_insert_id() immediately after the data is submitted to the database, you can then grab all the fields the user just submitted, define variables to them and then echo these variables within the email body, thus sending him a copy of the information he just entered (embedded within your html email of course)
If you want an example written, feel free to pm me.
HTH
Jonathen