Dyndns is a good option,
It doesn't require a static IP, they give you a unique name that you use to remote desktop instead (like myhome.dyndns.org)
Have you considered using a different remote desktop client?
There is a free service provided by a company called Logmein, where you install an application on your pc, then you can login to thier website and access your computer from anywhere, it doesn't matter if your IP changes daily. Or even if the PC was in different place. As long as its on and has an internet connection you will be able to connect to it.
Its also secure, using 256 bit encryption. We use it for corporate support (as well as other alternatives for different clients) but to just get access to your home pc, its by far the easiest option.
Hope this helps!
adxba