Seconding what Birger said about trying to host on your own computer. You should never, ever do that.
There are lots of different blogging engines and content management systems available out there. My favourite is
GeekLog, as it's a nice medium between being a blog and a proper community portal, and by enabling/disabling the various options (and with the installation of a couple of plugins here and there), you can make it swing either way.
You can test drive a bunch of blogs and content management systems at
OpenSourceCMS - Home, before deciding which one to install in your web space.
Here's where I'd plug my own hosting company a little bit, but I've already done that twice today, so I won't.
