PHP and the UNIX Timestamp

In regards to this tutorial, how would i be able to insert a value into mySQL using PHP, and using tis timestamp feature add that value to that inserted value, so that i know when it was entred!?! i hopw i’m making sense.

I have an application that inserts into a mySQL database, and a user will insert an event from a webpage interface that inserts data into my db using PHP, now i want to have an option, so that when a user inserts a new events that a date and time value be assigened to this event, so that when its retrived, it would print out: this event was entred on: October 10, 2005 at 12:22 !!