Remember the Milk beta makes your to-do items and reminders available in Gmail, via SMS, the iPhone, Windows Mobile devices, Skype, and popular IM clients. Integration with Google Calendar and contacts would let you connect to, say, a co-worker for an instant chat at an appointed time. Remember the Milk also can pinpoint tasks on a map and export your lists as Atom and iCal-ready feeds.
Remember the Milk is one of the most portable goal-setting services in its space; you can take it with you instead of repeatedly returning to its Web site. There are two levels of service, one free and one Pro that runs $25 a year. Pro members get early access to new features, technical support, as well as access to the service on Apple's iPhone.
Winner: Remember The Milk (RememberTheMilk.com)