I'm not registering yet, but I found a way to kind of keep tabs on things I want for when that time comes & thought I'd share!
I signed up with www.myregistry.com & you can add things from all different sites (it puts a button on your browser). Then there is also an app for your phone. I have a droid & I'm sure there's one for iPhone, too. With the app, you can use a barcode scanner to scan the barcode in a store with your phone camera. Then it adds it to your registry!
I'm not actually going to use the myregistry.com thing as a registry for people to buy off of, but more of a way for me to keep track of what stroller, crib, bedding, etc that I want.
It's really great when I'm out & about & want to check on the safety, reviews, etc of a product- I just scan it, and then when I get home, I can find that exact product online and do all my research!