Well, I can toss in a few cents on the parts that other's haven't touched.

I hate to say this, but there really is no way to block a visitor from a website. Yes, if you willing to go to the trouble and admin your host, you can block an IP or IP-range from accessing your server. That isn't hard to get around if you want- new ISP, or use any of a variety of anonymiser software, or the library, or a net cafe.... And if you don't admin your host, you will fight an uphill battle with them to get this done, just becuase it is can be a pain in the butt to do, and really doesn't stop them.

As for your contact information, if you own your domain, whois and other domain name agents used to let you see a lot of information about who the domain is registered to. Been a while since I had to try to bid on a domain name that was about to become free, so I don't know if that's changed.

Hate to be the barer of bad news, but if you have a cyberstalker, there really isn't a lot that can be done without the court on your side, and even then it isn't much.