how can i start my own forum

almost all free hosts allow us to host forums. If it have fantastico in it, it allows to install phpbb3 forums. You should consider a paid hosting if you want reliability and more features. You can try forumer.com for free forums.

If you have our own website check in the domain control area many forums are available to install and use for free like PhbBB

There are a lot of forum scripts available in the net. Or if you want, sign up to 110mb. . After you do that, go to website add ons. . Choose a forum script that you like and then the site will install it for you. If you have advanced knowlegde in php program that will be a big help. It requires mysql database. But for forum making services which is already made and ready to use, i dunno if they exist.