Take a look at no-ip.com and their No-IP Free package.
You can now get your own permanent sub domain at no cost (free of charge) and also have few email-ids @ your domain name.
What this means is that whenever you dial-up or DSL connect or Cable connect to your ISP, you can have your random IP address, say X.Y.Z.A always point to something like howkewl.hopto.org. How cool can it get ? :)
Also, take a look at the free DynDNS services for similar purpose.
I haven't tried their services. Do read the "Terms and Conditions" carefully and apply your usual discretion.