First you will need a domain name. You could buy 1 from somewhere like http://bravenet.com
Now you will need somewhere to host your site. Although Bravenet offers hosting, I wouldn't recomend it. Try http://TTLhosting.net
They are quite reasonable with price and they allow you to host adult sites.
If you want to build a community, you can get a free forum from http://www.simplemachines.org and a free portal to go with it from http://www.tinyportal.net
You can also add many mods such as chatrooms and gallerys etc.