Osmo is a handy personal organizer, which includes calendar, tasks manager, address book and notes modules. It was designed to be a small, easy to use and good looking PIM tool to help to manage personal information.
Gchore is a simple tool that tracks your chores, and reminds you to do them on a daily basis. It is not a general todo list, it is better suited for repeating tasks, such as taking out the garbage on mondays.