Here is one way to trace your dynamic IP address to find the host name. This is what people will type in their browser to access your site.
1. Go to http://www.network-tools.com
2. In the text box in the center of the screen, you will see the IP address you have been assigned by your ISP. This will automatically be captured and traced by the site
3. Check the dot to the left of the word, "Lookup".
4. Click on "Submit".
5. At the lower left of the screen, the site will come back with a report of the IP address and it's associated host name.
That is the name your visitors will have to type; or they can type the actual IP address. There is a lot of other useful information that can be gained from this site, such as:
Ping - This will send a packet request to the server and time the reply.
Trace - Will show the actual path taken between that site and yours.
Xwhois - To look up the ownership of a domain name or IP address.
There are also many definitions and explanations of various terms and operations.