For the perpetually lazy, most databases have some way of defining default values. (although, with dynamic values such as this, you might have to use a trigger).

In mysql, you can just use the column type TIMESTAMP.

It's been a while since I've played with oracle, but if setting the column 'DEFAULT SYSDATE' doesn't work. (It might've been 'DEFAULT SYSDATE()'), you can always use an insert trigger.