Change Timestamp to Now

How can I change the timestamp on a post to now?

I have a photoblog and have a lot of posts that are set as drafts. I would like an easy way to change the timestamp to whatever the time is now, so that the post would act like I had just started writing it.

I’m not looking for a way to show posts from the future, so this plugin won’t help any. I just want to be able to take a post that I started to write in the past and move the timestamp to now.