[Reverse IP DNS Tool – Find Domains That Share Your IP Address][1]:

This tool will find other domain names hosted on your IP address. Just enter a domain (www.example.com) or an IP address (127.0.0.1) to get a list of domain names that share the same IP address.

I spent way too much time looking for something like this… If you know of another one, leave a comment please!

[1]: http://www.seologs.com/ip-domains.html?domainname=66.122.14.30