The broadband modem arrived today. Setting it up was pretty simple, just plug it in and a few clicks. BT's OS X installer even works (their dialup one didn't, I had to manually open up their coookie to configure that). It only seems to be able to connect at 256kbps though, instead of the advertised 512. I'll give it a few days and see how that goes, since some ADSL modems need to be 'trained'.
Setting up the Apache webserver that's built into OS X was very easy. One click fired up the server, but then I had to spend a few minutes googling to finding out where the root directory was (inside /Library/Webserver/Documents/ if you're wondering). I then set up an account with no-ip.com to forward emandtim.no-ip.com to my broadband connection's IP. no-ip.com make a nice little utility which will monitor your connection and regularly report your IP address to no-ip.com (and thus update the emandtim.no-ip.com redirection). Pretty slick for a free service. I'm now downloading the 600MB Apple Developer Tools - apparently I need them to set up MySQL. With my half-speed broadband it's going to take 4 or 5 hours.