I haven't done it in a while, so I don't remember, but sometimes if you
press the parking brake on just enough to bring the light on on the dash,
the day time running lights won't come on.  Another way is to remove the DRL
fuse.  Why would you want to do it, however?  It's a safety feature, and a
mandatory one in some Provinces and States.  If I were you, I would check
your local laws before attempting to disable the system.

Try here:
http://www.lightsout.org/