How to edit my hosts-file?

Hello guys!
(I'm from sweden so I write to you in english, but feel free to answer in danish).

I do some development at home for a site that I plan to go live with. But since the site doesn't exists yet I would like to test it from localhost.
I got a tomcat running at localhost:8080 and my site is at: 127.0.0.1:8080/my-site

If I now would like to test it like it existed under a real domain? How do I specify the fictive doman in my C:\I386\HOSTS??

I have tried:
127.0.0.1:8080/my-site    www.mysite.com

But it does not seems to be correct.

Best regards
Fredrik