I agree with Maria. I received a wedding invitation once that had a separate sheet saying where the couple was honeymooning, how much it would cost to do everything they wanted, and links to where we could help pay for it (tours, massages, dinners, etc.). I think those are known as honeymoon registries, but it really put us off. We barely knew them at that....if I'm paying for a vacation it's gonna be mine . . . LOL!
Put it on your website. My bm's sent enclosures with my shower invitiations which etiquette says is the only time you should mail anything about a registry.
Definitely register though. I was against it, my mom insisted that some people who may not know you well enough appreciate it. So far, most of our registry gifts have come from the people who give courtesy gifts but only know one of us (parent's friends). Close friends may choose to get you something outside of the registry anyway, but you'd be surprised at how many registry gifts you'll get just for having one.