I'd say at least a month or two before you're due. I'm having three, actually. One on Nov. 8th, one on Nov. 15th, and one on Nov. 22nd. I'll be 34, 35, and 36 weeks on those days. That's probably a little late to some people, but I've had a normal healthy pregnancy and I'm probably not going to deliver early.
But yeah, a month or two is probably best because you'll have enough time to set everything up just in case you go in early. But you don't want to do it TOO early, because then you'll have a bunch of baby crap sitting around that's useless until your baby comes. It's also good to do it a little early, so if you need to return anything you can do so and buy new stuff without too many hassles.
at 1:38 PM on Oct. 27, 2008