[TurboFool]

XP Home and Vista Home Premium have no support for RDP. Only XP Professional, and Vista Business/Ultimate support it (not counting server OSes). So those of you on the Home OSes are out of luck anyway, unfortunately.

If you happen to upgrade, though, then I recommend NO-IP as noted by Darkflame. They even have a pretty good tutorial on their site on how to get it working.

As for the router and your internal IP, just because it's remained the same for a while doesn't mean it's static. You'll need to go into your network settings and assign a specific IP address, otherwise when you restart your computer you may get a completely different address. You'll also need to have your router forward port 3389 to that IP address.