Quick corrections: XP comes with IIS 5.1, not 6. 6 will be in .net server. and xp corp can actually be pro or home. The "corp" part refers to the licensing, and any business (or private person, for that matter) can purchase volume licensing, which is usually what that is. Basically, MS sends you a few extra keys, and you can opt to purchase a special CD that doesn't require authentication to MS servers. Generally this is done because MS can trust these buyers a bit more to only install the number of licenses they own (penalties for not having licensed software in a business can be mighty hefty)
BEFORE you install IIS, please PLEASE do a little research and just make sure you can find the resources on securing it. And FYI, you would have to do the same thing if you wanted to effectively use Apache for your web server.
Lastly, you can also use
everydns for your dynamic DNS needs. It's free, easy and effective. Do a few searches for hosting on the forum here and you'll pull up a buncha posts on similar topics, with snippets of relevant information. (A search for IIS will find you a post with several links that I'd posted before).
/Lactic