This article lists more than one way to run multiple web sites in IIS on a non-Server edtition of XP (i.e. Professional or Home). Previously I thought that this was not possible, but it turns out the limtation is in the IIS Admin Console GUI – not Windows – although Windows still will not let you run more than one site siultaneously. I downloaded and installed IIS Admin, and it is working great.
Why would you want to do this anyway? Well, in my case, I am completely re-architecting a site for my client, but I need to maintain the current version and we only have one development server and it is running XP Professional. IIS Admin allows me to set up and work on both sites on the development server. Since I can only have one running at I time and most of my time is spent creating the rearchited site, I keep it running by default. Whenever I need to make a change to the existing site, I just start it in IIS Admin, make and test the changes, and then upload them to the production server, and then switch back.