I think I bleed for 4 - 5 weeks, very heavy bleeding the first 2 weeks then like a normal period after. IT's your body cleaning everything out. I think people who have a c-section maybe worse, as their body doesn't kick all the gunk out as quick as a normal delivery.
OH and if you haven't been old yet, your next few periods after giving birth are VERY heavy! I've just finished my 2nd period and both times, I've had to still use maternity pads. MY first period, I had to call in sick for 3 days at work.