Hey CB,
You will need a server to host your website and a database to support a forum.
To kick-start (and I am assuming you are new to this) just get one of those 'learn-HTML-24-hours/days' books from the library and have a read.
You may alternatively, google it. Once you start creating pages, you can look for a service provider (plenty of them) to host your pages.
You can start scripting and perhaps get one of the web design software like dreamweaver/flash/fireworks at a later stage.
If I may suggest there are several blog sites which provide some nice templates and all you need to do is pick and paste. In which case you don’t have to worry about server etc. You can get started there and as you go you will fairly have a good idea of what you want in your site, understand who your audience will be and it will give you a better picture of how you should present your content.
Check this out
http://www.blogger.com/start
Sorry, if I am all over the place. I wish I could explain better ...and my apologies if I took too much liberty to explain unnecessarily