www.no-ip.com is amazing...
I use it for all my servers and DNS needs for cablemodem connection based servers.
web page is at:
http://team871.zapto.org/
web cam (just added today) is at
http://871cam1.zapto.org/
it is great. It is so useful that I actually paid the $20 fee to get be able to create more than 5 DNS redirects and get rid of the small pop-up that promotes
www.no-ip.com.
It is easy to use and very reliable, and no they don't pay me to say any of this :-)