DuckDNS[0] is another alternative that I've been seeing posted on reddit. Works exactly like the rest -- curl a URL to update your IP. Really nice staff. I've got a PR[1] for a homebrew formula for duckdns which uses launchd rather than cron (which has been deprecated since OSX 10.8).

[0] http://duckdns.org [1] https://github.com/Homebrew/homebrew/pull/28255