WordPress: Customize subject in new comment notification e-mails

What code should I use to customize the subject of notification e-mails in a WordPress blog?

I mean the e-mails sent to post authors when a comment has been left by someone on their post.

At the moment the subject is about:

[%site-title%] Comment: "%post-title%"‏

I'd like to use:

New comment is waiting for you

via Chebli Mohamed