Edit: It looks like I'm also happy that I chose to host my own CalDAV server, too.
Edit 2: @koenigdavidmj - Apparently I can't reply that deeply. DAViCal is the CalDAV server I'm using (http://www.davical.org/). My wife and I sync our iPhones to it and it's been a godsend for my personal organization. (Now if I could just find a decent replacement for Mozilla Sunbird...)