how do i find the url for my iMac

Can you explain in more detail what you mean? A URL is the address of a website - such as Apple.com or Harvard.edu. A computer will only have a URL if it has been set up as a web server and has name servers pointing to it (so that people looking for yourcomputer.com will be sent to the right place).

Conversely, every computer has an IP address, which is numerical. If you're connected directly to your internet, you will have a public IP address (it might look like 245.46.120.30, for example). Most people connect to the internet through a router, though, which gives them a private IP address only visible within their own network (something like 192.168.1.4).

Matt

A computer does not have a URL...a website has a URL.

What exactly are you looking for?

If you want the serial number for your iMac, click the apple at the left side the menu bar, About This Mac, and under the apple, and under OS X there is the version of Mac OS X. Click that and you will see the Build, click again and you see the serial number.

To find your public IP address (what your internet provider gives you), you can visit a website such as http://whatsmyip.org.

To find your private IP address (what your router gives you), open System Preferences and click on Network. The wifi (if you're wireless) entry should tell you what your local IP address is.

I'm curious why you're looking for the address, though?

Matt