I had a problem installing IIS and as it was asking for the XP SP3 CD, I downloaded SP3, slipstreamed with my existing XP install files, and burnt a new bootable CD. And I hardly need record that IIS still wouldn't bloody well install. An illustration of the nightmare is given in this thread on the MS Community forum. Check out the tizzy some of the participants get into. The solution for me was given in the penultimate post in this long thread and it may be reached with this link.
Of course I had forgotten how set folder security through IIS, and I hadn't a clue which port was being used. The answers were provided for me in this thread in the MS forum (whatever faults MS may have, and despite the large egos of the some of its users, the forum is an excellent resource). I duly copied my web to inetpub (in a subfolder called myweb), allowed anonymous access, allowed access through port 80 in the Windows firewall, and mapped port 80 to the appropriate pc in my router.
To my amazement, not only could I view the web on my local network but also using my wan IP address. I am so pleased, I'll put a link here, although in case anyone wants to look at the site when my computer is turned off, I'll put a link to the ISP hosted version here.
Adding the JNLP MIME type was a bit more tricky. I seem to be the only person in the world still using IIS 5.1. For those using later editions here is a blog giving cryptic instructions, here is a discussion on the topic and here is a set of instructions which didn't apply to me but gave useful clues. But I can't test what I have done yet, because I haven't created the jnlp file.