Personally, I use Webmin and Virtualmin (Google them). It is a fairly simple system, but quite powerful.
LOL, I could have used this tutorial a year ago. I had to figger all this stuff out myself. But it works great, and I host my personal site, as well as several forums on my 512Kb uplink connection. I have maybe 20 users on at once, and it hasn't caused any bandwidth problems. (This depends on your site though, if it's graphics-heavy there will be much higher bandwidth consumption.)
I first started with Abyss on a Windows system, but later I compiled some spare parts into a 1 GHZ system with 512MB ram and a 40 gig hard drive. I run Fedora Core 4 on it, which has proven to be very easy, as it comes with all the servers allready configured. As far as the IP goes, I use freedns.afraid.org, which offers a free dynamic IP service. My ISP charges $20 a month for 1 static IP, which is the same as the internet access!